Category: Class 11 Chemistry Objective Questions

Chemistry Questions & Answers for Exams on “States of Matter – Intermolecular Forces vs Thermal Interactions”.

1. What is the result of balancing between intermolecular forces and thermal energy?
a) matter
b) three States of matter
c) four States of matter
d) chemical bond formation
Answer: b
Clarification: In a molecule, intermolecular forces always tend to keep molecules with each other while the thermal energy always tries to separate them. So the result of balancing between intermolecular energy and thermal energy is three States of matter.

2. Which state of matter is likely to form when there is a predominance of intermolecular energy?
a) solid
b) liquid
c) gas
d) both solid and gas
Answer: a
Clarification: When there is a predominance of intermolecular energy in the matter, the order of states of matter that are the likely to form is solids, liquids and then gases. It follows reverse order in case of the predominance of thermal energy.

3. A gas can be liquefied only through an increase in compression.
a) true
b) false
Answer: b
Clarification: The above statement is false because gas cannot be liquefied only through compression, even the temperature needs to be lowered in order to compress the gas. This is because of the reaction of intermolecular forces and thermal energy between the molecules.

4. Gas is readily formed in case of predominance of ___________
a) intermolecular energy
b) thermal energy
c) both intermolecular energy and thermal en energy
d) neither intermolecular energy nor thermal energy
Answer: b
Clarification: In the case of the predominance of thermal energy, the gas is likely to be formed rather than liquids and solids. This happens because the thermal energy tends to separate the molecules in a substance.

5. In the case of ice which energy do you think that is predominant?
a) Thermal energy
b) Intermolecular energy
c) Intermolecular energy
d) Heat energy
Answer: b
Clarification: In case of ice the molecules are tightly packed and we do know that in solid the intermolecular forces are so high that they are tightly packed so intermolecular energy is predominant in case of ice.

6. The following are the temperatures of milk in Celsius. In which of the following, do you think intermolecular forces are predominant than thermal energy?
a) 35
b) 82
c) 50
d) 9
Answer: d
Clarification: The rise in temperature depicts thermal energy. So among the given options at 82 degrees Celsius the milk has the highest thermal energy and at 9 degrees Celsius the milk has higher intermolecular energy. So at 9 degrees, the intermolecular forces are predominant than thermal energy in milk.

7. What is a term used for the conversion of solid into gas directly?
a) Evaporation
b) Sublimation
c) Condensation
d) Melting
Answer: b
Clarification: The process of direct conversion of solid to gases is sublimation while the process of conversion of liquid to gas is evaporation whereas the process of conversion of solid to liquid is melting and liquid to solid is condensation.

8. Particles in a solid __________
a) are tightly packed
b) are loosely packed
c) move continuously
d) collide with each other
Answer: a
Clarification: When there is a predominance of intermolecular energy instead of thermal energy, the molecules are tightly packed and have a definite shape and structure; these are called solids. So in solid, the particles are tightly packed.

9. Compressibility is high in case of ___________
a) solids
b) liquids
c) gases
d) both solids and liquids have the same amount of compressibility
Answer: c
Clarification: Compressibility is high in the case of gases because thermal energy is predominant in gases. This energy enables the molecules of gases to move away from each other so that when compressed together they compress easily by reducing the distance between each other comparatively.

10. During the process of freezing the temperature is _________
a) constant
b) increasing
c) decreasing
d) irregular
Answer: a
Clarification: During the process of freezing the water, water converts into ice that means new bonds are creating during this process and the temperature remains constant but the internal energy changes during this phase.

To practice all exam questions on Chemistry,

Chemistry Multiple Choice Questions & Answers (MCQs) on “Thermodynamic Terms”.

1. Which of the following property cannot be used to describe the state of a system?
a) pressure
b) volume
c) temperature
d) universal gas constant
Answer: d
Clarification: State functions are used to specify the state of a thermodynamic system. The state is described by measurable macroscopic particles like pressure, temperature, volume, amount, etc and the is P, V and T are called state variables.

2. When work is done on system or by a system there is a change in _________
a) external energy
b) internal energy
c) adiabatic energy
d) isothermal energy
Answer: b
Clarification: When a work is done or by the system, heat passes into out of the system and matter enters or leaves the system, there is a change in internal energy of the system. It is represented by the symbol “U”.

3. The system that does not allow the heat to pass through its boundary between the system and surroundings is called as ______________ system.
a) adiabatic
b) open
c) isothermal
d) close
Answer: a
Clarification: An adiabatic system does not allow the exchange of heat between system and surroundings. Energy is transferred to the surrounding only through work Done. In the adiabatic process, the total energy is given as zero.

4. In an adiabatic process the work done is 50 KJ, what is its internal energy?
a) 50 KJ
b) 25 KJ
c) -50 KJ
d) -25 KJ
Answer: c
Clarification: The total energy in an adiabatic process is zero, so internal energy is equal to the negative of the work done. Here work done is given by 50 kilojoules, so the internal energy is -50 kilojoules as the sum of internal energy and the work done should be zero.

5. An adiabatic process pressure is related to volume as _________
a) PV = constant
b) PV^γ constant
c) PV³ constant
d) PV² constant
Answer: b
Clarification: Let P is pressure and V is volume whereas Gamma is the ratio of specific heat capacity at constant pressure and volume. The relation between pressure and volume in an adiabatic process is given by PV^γ constant.

6. The first law of thermodynamics states that the energy of an isolated system is constant.
a) true
b) false
Answer: a
Clarification: The first law of thermodynamics is commonly stated as the law of conservation of energy that is energy can neither be created nor be destroyed, in other terms we can also say that the energy of an isolated system is constant.

7. An open system allows the transfer of ________
a) only mass
b) only energy
c) both mass and energy
d) neither mass nor energy
Answer: c
Clarification: An open system allows the transfer of both mass and energy into the system from the surroundings. An example of an open system is the human body, we consume food, energy and excrete waste.

8. Both isolated and closed systems are the same.
a) True
b) False
Answer: b
Clarification: An open system allows only energy transfer whereas an isolated system neither allows energy nor mass transfer through the system from the surroundings. Isolated and closed systems are not the same. So the above statement is false.

9. If the work is done on an adiabatic wall, then which of the following is true?
a) ΔU = -W
b) ΔU = W
c) ΔU + W = 0
d) ΔU = -W
Answer: b
Clarification: In an adiabatic process, the total energy is always zero. We have that ΔH = ΔU + W, as ΔH is zero, we get ΔU + W = 0; ΔU = -W. But as work is done on the system by observing no heat W becomes negative, so ΔU = -(-)W = W. Hence ΔU = W.

10. The temperature of an object increases slowly, then the energy of that object _________
a) increases slowly
b) decreases quickly
c) increases quickly
d) decreases slowly
Answer: a
Clarification: Energy of a substance is directly proportional to its temperature. As we know that heat energy of a substance is q = mcΔT. If the temperature increases slowly then the energy also increases slowly.

Chemistry Multiple Choice Questions on “Equilibrium – Ionization of Acids and Bases”.

1. What is the value of the ionic product of water at 298k?
a) 7 x 10^-14/mol²L²
b) 1 x 10^-10/mol²L²
c) 1 x 10^-14/molL²
d) 1 x 10^-14/mol²L²
Answer: d
Clarification: Ionic product is a product of the concentration of hydronium ions and hydroxyl ions in pure water, which remains constant at a particular temperature. It is symbolized as K_W and is equal to 1 x 10^-14/mol²L².

2. The ionization constant of water increases with increase in temperature.
a) true
b) false
Answer: a
Clarification: The ionization product of water is given by [H₃O⁺][OH^–] = 1 x 10^-14/mol²L² at 298 k, the product of the concentration of hydronium ions and hydroxyl ions in pure water. Concentrations increase with temperature, so the ionization constant of water increases with increase in temperature.

3. Write pH in terms of concentration of hydrogen ion?
a) [H⁺] = 1^-pH
b) [H⁺] = 10^-pH
c) [H⁺] = 10^pH
d) [H] = 10^-pH
Answer: b
Clarification: pH is defined as the negative logarithm of hydrogen ion concentration that is pH = -log[H⁺]. By rearranging pH in terms of concentration of hydrogen ions, we get [H⁺] = 10^-pH. pH means potential of hydrogen.

4. What is the pK_W at 298 k?
a) 14
b) 7
c) 1
d) 0
Answer: a
Clarification: We know that the ionization constant of water at 298 k is given by [H₃O⁺][OH^–] = 1 x 10^-14/mol²L². pK_W = pH + pOH = -log[H₃O⁺] – log[OH^–] = -log[H₃O⁺][OH^–] = -log10^-14 = log10¹⁴ = 14. Therefore pK_W at 298 k is 14.

5. Which of the following has a PH greater than 7?
a) gastric juice
b) vinegar
c) blood plasma
d) lemon juice
Answer: c
Clarification: Acids always have a pH below 7 and bases have a pH of above 7, while neutral compounds have a pH of 7. Here gastric juice, vinegar, and lemon are acids, so they have a pH of below 7, but blood plasma is a base. It has a pH greater than 7.

6. A neutralization reaction results in the formation of _______________
a) salts
b) acid
c) base
d) hydrogen
Answer: a
Clarification: Salts are the products of the reaction between an acid and a base, these type of reactions are called neutralization reactions. There are many types of salts like normal, acidic, basic, double, complex and mixed salts.

7. NaCl is a ________ salt.
a) Normal
b) Acidic
c) Basic
d) Double
Answer: a
Clarification: Normal salts like NaCl are obtained by complete neutralization of an acid with a base. Acidic salts are formed by incomplete neutralization of polybasic acids and basic salts are formed by incomplete neutralization of poly acidic base. Double salts are formed by the combination of two simple salts and exist only in the solid state.

8. What is the reverse process of Neutralization?
a) formation
b) hydrolysis
c) reaction
d) splitting
Answer: b
Clarification: Salts are strong electrolytes and on dissolution in water split up into ions. Which react with hydrogen ions are Hydroxide ions furnished by water yielding an acidic or basic solution. This process is called salt hydrolysis and is the reverse process of neutralization.

9. Why is the aqueous solution of a salt of a weak acid and strong base is alkaline?
a) utilization
b) neutralization
c) cationic hydrolysis
d) anionic hydrolysis
Answer: d
Clarification: The aqueous solution of a salt of a weak acid and strong base is alkaline, due to the anionic hydrolysis and aqueous solution of a salt of a strong acid and weak base is acidic, due to cationic hydrolysis with dilution degree of hydrolysis increases.

10. What is the hydrolysis constant of a weak acid-weak base?
a) K_W/K_b
b) K_W/K_a
c) K_W/K_aK_b
d) 1/K_aK_b
Answer: c
Clarification: The hydrolysis constant of a weak acid and weak base is K_W/K_aK_b, the degree of hydrolysis is √K_W/K_aK_b and the pH of the solution is given by 1/2pK_W + 1/2pK_a – 1/2pK_b. An example of a salt of a weak acid and a weak base is CH₃COOHNH₄.

11. Formic acid has a concentration of 0.1M and K_a is 1.77 x 10^-4. What is the value of degree of dissociation?
a) 4
b) 4.2
c) 0.42
d) 42
Answer: b
Clarification: The dissociation constant K = [H⁺][HCOO^–]/[HCOOH] = x²/0.1 – x = 1.77 x 10^-4; x = [H⁺] = 0.0042M. The percent of dissociation is x/0.1 = (0.042M)100% = 4.2. Therefore the value of degree of dissociation is 4.2

12. What is the pH of the solution of sulphuric acid having a concentration of 0.01M?
a) 1
b) 2
c) 3
d) 4
Answer: b
Clarification: pH is defined as the negative logarithm of hydrogen ion concentration that is pH = -log[H⁺]. So here, the pH of the solution of sulphuric acid is -log[H⁺], where concentration of hydrogen ion is 0.01M = -log[10^-2] = 2.

13. Acetic acid’s pK_a is 4.2 and ammonium hydroxide pK_b is 3.24. What is the pH of the ammonium acetate solution?
a) 7.12
b) 7
c) 4.2
d) 7.48
Answer: d
Clarification: We know that the pH of the solution of a weak acid and a weak base is given by 1/2pK_W + 1/2pK_a – 1/2pK_b. So pH = 7 + (frac{1}{2})[4.2 – 3.24]; pH = 7 + 0.48 = 7.48, we get this by substituting acetic acid’s pK_a as 4.2 and ammonium hydroxide pK_b as 3.24.

14. Acid strength increases in the order of _____________
a) HF ≪ HCl ≪ HBr ≪ HI
b) HF ≪ HBr ≪ HCl ≪ HI
c) HI ≪ HCl ≪ HBr ≪ HF
d) HCl ≪ HF ≪ HBr ≪ HI
Answer: a
Clarification: The correct order of increase in acidic strength is HF ≪ HCl ≪ HBr ≪ HI. There are many factors affecting acid strength. Hear the hydrogen-acid Bond strength decreases, as the acid strength increases.

Chemistry Multiple Choice Questions on “s-Block Elements – Biological Importance of Sodium and Potassium”.

1. How much iron do you think a 70 kg man contains?
a) 4 gram
b) 3 gram
c) 5 gram
d) 2 gram
Answer: c
Clarification: An ideal person, who is of 70 kg contains about 90 grams of sodium, 5 grams of iron, 170 grams of potassium and 0.06 grams of copper. We can say that there is a great biological importance of alkali metals.

2. Which of the following metal helps to transmit nerve signals?
a) hydrogen
b) potassium
c) sodium
d) lithium
Answer: c
Clarification: Sodium, being an alkali metal has many biological uses like nerve signal transmission, also in water flow regulation across cell membranes along with the Sugars and amino acids’ transportation into cells.

3. Sodium and potassium have the same mobility in case of penetration into cell membranes.
a) true
b) false
Answer: b
Clarification: Though potassium and sodium are similar chemically, they differ in their ability to penetrate the cell membrane and also in the mechanism of their transport. Potassium is more efficient in case of activating enzymes.

4. How much ATP does Sodium-Potassium pump consume?
a) three fourth
b) one fourth
c) one third
d) half
Answer: c
Clarification: The Sodium-Potassium pump operates across cell membranes and consumes around one-third of the ATP used by a resting person. Sodium ion and potassium ions levels change within red blood cells because of the discriminatory mechanism called is the Sodium-Potassium pump.

5. Which elements compounds are used for treating disorders?
a) nitrogen
b) lithium
c) sodium
d) potassium
Answer: b
Clarification: Lithium carbonate is a drug which is used to treat depressive disorders for Hypertension, lithium chloride is also used as a treatment. Lithium cannot be consumed directly because it has an effect on the body.

6. Which of the following is not treated using higher levels of potassium?
a) cold
b) hypokalemia
c) muscle contraction
d) respiratory paralysis
Answer: a
Clarification: Muscle weakness, paralytic ileus, acidosis, ECG abnormal 38, inflammatory bowel diseases, respiratory paralysis, alkalosis, cardiac ahead, renal damage, muscle contraction, and hypokalemia are treated using higher levels of potassium.

7. Can potassium bicarbonate be used as an antacid?
a) Yes
b) No
c) Maybe
d) May not be
Answer: a
Clarification: Potassium carbonate can be used instead of sodium carbonate as an antacid, in case if the person who has to consume antacid is restricted to consume sodium. This is because Sodium and potassium belong to the same group and have similar properties.

8. Francium has __________ biological importance.
a) great
b) no
c) extreme
d) huge
Answer: b
Clarification: There is no biological importance of the alkali metal francium. Francium is a highly radioactive element and its chemical hazards are similar to those of cesium. Francium is not available to a significant extent in the biosphere.

9. Can cesium be ingested?
a) obviously
b) certainly
c) no
d) yes
Answer: c
Clarification: No, cesium cannot be ingested, it should be avoided this is because the similarity of the isotopes of cesium present in the biosphere is very toxic and there ingestion can be dangerous and hazardous.

10. Which of the following metal readily reacts with skin moisture to form rubidium hydroxide?
a) lithium
b) rubidium
c) sodium
d) potassium
Answer: b
Clarification: Rubidium accumulates in muscle ahead of potassium and it can stimulate metabolism. It also readily reacts with skin moisture in order to form rubidium hydroxide. This is the biological importance of the element rubidium.

Chemistry Exam Questions for NEET Exam on “Methods of Purification of Organic Compounds”.

1. The purification method where solid substances change from solid to vapor state without passing through the liquid state is called as which of the following?
a) Sublimation
b) Crystallization
c) Distillation
d) Differential extraction
Answer: a
Clarification: In sublimation, the solid substance transforms directly to the vapor state without entering into the liquid state. This helps in separating sublimable compounds from non-sublimable ones. Whereas the other three, i.e. crystallization, distillation and differential extraction are used when a suitable solvent is involved. In other words, they deal with mainly liquids and not solids alone.

2. In crystallization, the compound dissolved in a solvent is more soluble in what temperature?
a) Room temperature
b) Lower temperature
c) Higher temperature
d) Very low temperature
Answer: c
Clarification: When a compound is dissolved in water, solubility increases with increase in temperature. This is because, when the temperature increases, the kinetic energy also increases which in turn helps the solvent molecules to break apart the solute molecules more efficiently than in other cases. These solute molecules are held together by intermolecular interactions which requires greater energy to be broken off and hence, higher temperature.

3. What is the basis for the process of distillation?
a) Difference in melting point
b) Difference in temperature
c) Difference in pressure
d) Difference in boiling point
Answer: d
Clarification: The process of distillation is based on the difference in the boiling points of the liquids. This is because, liquids having different boiling points vaporize at different temperatures. In this way, the vapors cooled can be collected separately from the liquid formed. Crystallization is used to separate volatile liquids from non-volatile liquids as well.

4. In fractional distillation, vapors of low boiling point component ascend to the top of the column.
a) True
b) False
Answer: a
Clarification: Fractional distillation, like normal distillation is also based on the difference in boiling point of the liquids. The only difference in fractional distillation is that, the liquids associated with this method have lesser difference in boiling point than the liquids involved in normal distillation. So, the high boiling point liquids condense at the bottom while the low boiling point liquid condense all the way to the top of the distillation column.

5. Identify the example of compounds separated by steam distillation method.
a) Glycerol-spent lye mixture in soap industry
b) Aniline-water mixture
c) Chloroform and aniline mixture
d) Different fractions of crude oil in petroleum industry
Answer: b
Clarification: Aniline and water mixture is separated by employing the process of steam distillation. Steam distillation method is used when the substances involved are steam volatile and immiscible in water. Aniline satisfies both these conditions and, hence, this method is used to separate aniline from aniline-water mixture. Glycerol-spent lye mixture is an example of distillation under reduced pressure, chloroform and aniline mixture employs simple distillation, and crude oil separation involves fractional distillation method.

6. Which of the following is the apparatus for differential extraction?
a) Separatory funnel
b) Porous sheet
c) Packed column
d) Electric motor
Answer: a
Clarification: A seperatory funnel is used in differential extraction. Differential extraction involves separating the immiscible organic compound from the aqueous solvent. The separating funnel aids in this process of separating immiscible liquids. It also helps in layer formation, with the denser solvent at the bottom and the other on top. This layer formation is important for the process, and thus, separatory funnel is chosen as the apparatus for differential extraction.

7. Which is not used as an absorbent in adsorption chromatography?
a) Silica gel
b) Alumina
c) Potassium permanganate
d) Starch
Answer: c
Clarification: A good adsorbent requires large surface area, should be easily available, less expensive. They should also be thermally stable, and have high abrasion resistance. Silica, alumina, and starch possesses these characteristics while potassium permanganate does not, so it cannot be an adsorbent.

8. In column chromatography, identify the mobile and stationary phase from the following.
a) Solid, Liquid
b) Liquid, Solid
c) Gas, Liquid
d) Solid, Solid
Answer: b
Clarification: In column chromatography, the mobile phase is made out of liquid or a mixture of liquids which is allowed to flow down the column, and the stationary phase consists of solid, that is the adsorbent(alumina or silica gel) over which the liquid(mobile phase) flows.

9. Thin layer chromatography is used to estimate drugs in formulation.
a) True
b) False
Answer: b
Clarification: Estimation of drugs in formulation is done by column chromatography. Thin layer chromatography is used to detect amino acids by spraying the glass plate with ninhydrin solution. Thin layer chromatography involves the use of a glass plate, called as chromaplate.

10. Paper chromatography is a type of which chromatography?
a) Column chromatography
b) Thin layer chromatography
c) Adsorption chromatography
d) Partition chromatography
Answer: d
Clarification: Paper chromatography is a type of partition chromatography. This is because, they spend more time in the stationary phase than the mobile phase. Also, they won’t travel very fast up the paper. Partition chromatography employs the method of separation by making use of the partition of the solutes between the two liquid phases.

11. The mobile phase in chromatography can comprise of which of the following?
a) Gas or liquid
b) Liquid or solid
c) Solid or gas
d) Liquid only
Answer: a
Clarification: The function of the mobile phase in chromatography is to flow over the stationary phase through the packed bed or column. So, only fluids (liquid or gas) can be employed as mobile phase whereas solids cannot be mobile phase, simply due to its inability to flow like fluids and also the interaction with the stationary phase (solid or liquid) will be affected and hence, solids cannot be used as mobile phase.

12. Which type of chromatography involves the separation of a mixture over a column of adsorbent packed in a glass tube?
a) Thin layer chromatography
b) Partition chromatography
c) Column chromatography
d) Gas liquid chromatography
Answer: c
Clarification: Column chromatography involves the separation of a mixture over a column of adsorbent packed in a glass tube. The mixture adsorbed on the adsorbent is placed at the top of the column and the mobile phase is allowed to flow through the column slowly.

13. Gas chromatography can be performed in X, whereas liquid chromatography can be performed in Y. Identify X and Y.
a) X = only plane surfaces, Y = only columns
b) X = only columns, Y = only plane surfaces
c) X = only columns, Y = columns or plane surfaces
d) X = columns or plane surfaces, Y = only plane surfaces
Answer: c
Clarification: Gas chromatography can be done only in columns because in this method, the sample is vaporized and injected onto the top of the chromatographic column. It could be gas-liquid or gas-solid chromatography. Liquid chromatography has liquid as the mobile phase where sample ions or molecules are dissolved. So, it can be carried out either in a column or a plane.

14. What is the paper strip developed in partition chromatography called?
a) Chromatograph
b) Chroma
c) Chromatographing strip
d) Chromatogram
Answer: d
Clarification: The paper strip so developed by retaining different components according to their different partitions in the two phases is called a chromatogram. The spots of the separated colored components are visible at different lengths from the location of the initial point on the chromatogram.

15. Which is the most suitable carrier gas in gas chromatography?
a) Helium
b) Nitrogen
c) Oxygen
d) Carbon dioxide
Answer: a
Clarification: In gas chromatography, the carrier gas should be an inert gas which does not react with the sample. Even though nitrogen and some other gases are also used, 90% of the instruments use helium as the carrier gas. Hydrogen is preferred for improved separations.

To practice Chemistry Exam Questions for NEET Exam,

Chemistry Quiz on “Properties of Matter and their Measurement”.

1. Which of the following may not be a physical property?
a) Odor
b) Color
c) Density
d) Composition
Answer: d
Clarification: Composition is a chemical property because we can’t find a compound’s composition just by looking at it. We need to run some chemical tests to find out. Odor, color, and density are physical properties, as we can find them just by looking at them.

2. The observation of __________ properties needs a chemical change to occur.
a) Chemical
b) Physical
c) Extrinsic
d) Intrinsic
Answer: a
Clarification: Chemical properties are combustibility, composition, reactivity with acids & bases, etc. So to observe them chemical change has to occur. Combustibility can be known only when extinguished with fire. Composition is a chemical property because we can’t find a compound’s composition just by looking at it. We need to run some chemical tests to find out etc

3. Candela is the S.I. unit of _____
a) Luminous intensity
b) Thermodynamic temperature
c) Amount of substance
d) Electric current
Answer: a
Clarification: Candela is an S.I. unit of luminous intensity with symbol cd. It’s termed a source emitting monochromatic radiation at frequency 540 x 10¹² Hertz with the radiant intensity of 1/683 watt per steradian provided in the same direction.

4. How many scientific fundamental quantities are given S.I. units?
a) 5
b) 7
c) 3
d) 9
Answer: b
Clarification: There are seven scientific fundamental quantities i.e. Length(l), Time(t), Mass(m), Electric current(I), Thermodynamic temperature(T), Amount of substance(n) & Luminous intensity(I_v). They can’t be expressed as other quantities i.e. independent.

5. What is the symbol of the amount of substance’s S.I. unit?
a) K
b) s
c) mol
d) kg
Answer: c
Clarification: As the S.I. unit of the amount of substance is a mole, it’s denoted by “mol”. A mole is defined as many elementary entities as there are atoms in 0.012 kilograms of carbon-12.

6. What are the multiples for the prefixes yocto, atto respectively?
a) 10^-24, 10^-18
b) 10^-9, 10^-15
c) 10^-15, 10^-24
d) 10^-24, 10^-21
Answer: a
Clarification: Yocto is 10 power (-24) and atto is 10 power (-18). These are the standard prefixes used in S.I. system.

7. 1Litre = _______ m³.
a) 1000
b) 0.001
c) 1
d) 10
Answer: b
Clarification: As 1 litre is 1000ml
1000ml = 1000cm³
1000cm³ = 0.001m³
Therefore 1L = 0.001m³.

8. What is the difference in units between Kelvin and centigrade scales of temperature?
a) 212.15
b) 32
c) 298
d) 273.15
Answer: d
Clarification: Kelvin = Centigrade + 273.15. So the difference between in units between Kelvin and centigrade scales of temperature is 273.15.

9. What is the human body temperature in Fahrenheit?
a) 212
b) 98.6
c) 273.15
d) 32
Answer: b
Clarification: Our human body’s temperature is 37°C = 98.6°F = 310K. It’s a known fact and is the same for every human.

10. Convert 40°C to °F.
a) 104K
b) 313°F
c) 104°F
d) 313K
Answer: c
Clarification: 1 Fahrenheit = 9/5 Centigrade + 32.
9(40)/5 + 32 = 9 x 8 + 32 = 104°F.

11. S.I. unit of density is kg.m^-3.
a) False
b) true
Answer: b
Clarification: As density is the ratio of mass and volume, it’s S.I. unit is kg.m^-3, as the S.I. unit of mass is kg and the S.I. unit of volume is m³.