Category: Class 12 Chemistry Objective Questions

Chemistry Multiple Choice Questions on “Application of d and f-Block Elements”.

1. Which metal is used in an aircraft turbine engine?
a) Iron
b) Thorium
c) Titanium
d) Neodymium
Answer: c
Clarification: Titanium is one such material which plays a pivotal role in modern jet engine design. Its strength to weight ratio and resistance to extreme heat make it the ideal candidate for aerospace applications. Hence, it is used in aircraft turbine engines.

2. Mild steel is used in construction.
a) True
b) False
Answer: a
Clarification: Plain Carbon Steel is the most common type of steel used in building construction, which is also known as mild steel. It is incalculably strong and durable, and ensures a sturdy built and used in various type of construction.

3. Which metal is used as an electroplated protective coating?
a) Plutonium
b) Chromium
c) Nickel
d) Iron
Answer: b
Clarification: Chrome plating (less commonly chromium plating), often referred to simply as chrome, is a technique of electroplating a thin layer of chromium onto a metal object. The chromed layer can be decorative, provide corrosion resistance, ease cleaning procedures, or increase surface hardness.

4. Which metal is used in making electrical fibres?
a) Actinium
b) Nickel
c) Thorium
d) Tungsten
Answer: d
Clarification: The melting point of Tungsten (W) is very high (3422°C). It has the highest melting point among all the metals. This property of Tungsten makes it excellent for use as filaments in light bulbs as it can resist high temperatures.

5. Silver bromide is used in photography.
a) True
b) False
Answer: a
Clarification: Silver bromide (AgBr), a soft, pale-yellow, water-insoluble salt well known (along with other silver halides) for its unusual sensitivity to light. AgBr is widely used in photographic films and is believed by some to have been used for making the Shroud of Turin.

6. Which of the following metal does not form a coloured salt?
a) Thorium
b) Zinc
c) Bronze
d) Cobalt
Answer: b
Clarification: Zinc has no unpaired electrons in its d orbital and has a stable fully filled d orbital. Hence, due to the absence of unpaired electrons in Zinc, it can show no specific colouration in its salts. All salts and solutions of Zinc are always white due to this fact.

7. Which of the following is used as a nuclear fuel?
a) Cobalt
b) Zinc
c) Iron
d) Uranium
Answer: d
Clarification: Uranium (atomic no. 92, symbol-U) is used as nuclear fuel. Its salts are used in the glass industry (for imparting green colour), textile industry, ceramic industry and in medicines. Natural uranium has three major isotopes.

8. Which of the following has the highest density?
a) Os
b) Zn
c) Cr
d) Cd
Answer: a
Clarification: Osmium is the densest naturally occurring element, with an experimentally measured (using x-ray crystallography) density of 22.59 g/cm³. Its atoms are packed together more tightly in the solid form than other metals.

9. Which of the following element has the highest melting point?
a) Co
b) Zn
c) Ni
d) Cr
Answer: d
Clarification: Of all the 3d transition elements, chromium has the highest melting point. More the number of unpaired electrons in the d-block element, stronger is the metallic bond formation. Since chromium contains more number of unpaired electrons, it has the highest melting point.

10. What is the end product formed when KMnO₄ reacts with HCl?
a) Brown fumes
b) Dark green gas
c) Greenish yellow gas
d) Dense white fumes
Answer: c
Clarification: Potassium permanganate (KMnO₄) reacts with hydrochloric acid(HCl) to form potassium chloride, manganese chloride, chlorine and water. Here, one of the products formed, chlorine, is a greenish yellow gas. It has a pungent smell and is toxic.

Chemistry Multiple Choice Questions on “Methods of Preparation of Haloalkanes”.

1. What is the correct order of reactivity of alcohols with a given haloacid?
a) 1° > 2° > 3°
b) 3° > 2° > 1°
c) 1° > 3° > 2°
d) 2° > 1° > 3°
Answer: b
Clarification: When more number of electron donating groups are bonded to the C atom attached to the OH group, the polarity of C-OH bond increases. Thus, the reactivity of the alcohol increases.

2. What is the correct order of reactivity of the following haloacids with a given alcohol?
a) HCl > HBr > HI
b) HI > HBr > HCl
c) HBr > HCl > HI
d) HI > HCl > HBr
Answer: b
Clarification: The bond dissociation enthalpy of the carbon-halogen bond between H and Cl is the highest and that between H and I is the lowest among HI, HBr and HCl.

3. What is the catalyst in the reaction of a primary alcohol with HCl to obtain a chloroalkane?
a) anhydrous ZnCl₂
b) concentrated H₂SO₄
c) red phosphorous
d) pyridine
Answer: a
Clarification: The presence of anhydrous ZnCl₂ is to be break the C-O bond in alcohols. ZnCl₂ is a Lewis acid and reacts with the oxygen of the alcohol group.

4. The reaction of a primary alcohol with which of the following gives purely a haloalkane?
a) Phosphorus trichloride
b) Phosphorus pentachloride
c) Thionyl chloride
d) Sulphuryl chloride
Answer: c
Clarification: The reaction of alcohol with SOCl₂ gives a chloroalkane along with gases SO₂ and HCl which are easily escapable, leaving behind the pure alkyl chloride.

5. When ethanol reacts with PCl₅, it gives three products which include chloroethane and hydrochloric acid. What is the third product?
a) Phosphorus acid
b) Phosphoric acid
c) Phosphorus trichloride
d) Phosphoryl chloride
Answer: d
Clarification: The reaction of CH₃CH₂OH with PCl₅ yields CH₃CH₂Cl, POCl₃ (phosphoryl acid) and HCl. This is a method of preparation of chloroalkanes from alcohols.

6. What do you get by heating a mixture of hexanol and concentrated aqueous hydrogen chloride?
a) Cyclochlorohexane
b) Chlorohexane
c) Phosphorus acid
d) No reaction
Answer: b
Clarification: Alkyl chlorides can be prepared by heating a mixture of alcohol and concentrated aqueous halogen acid.

7. Iodoalkanes can be obtained by heating alcohols with potassium iodide in __________
a) hypophosphrus acid
b) phosphorus acid
c) phosphoric acid
d) hypophosphoric acid
Answer: c
Clarification: When alcohols are heated with potassium or sodium iodide in 95% phosphoric acid (H₃PO₄), iodoalkanes are generated.

8. The following reaction to form haloalkanes is an example of which type of reaction?
Propane + Cl₂ (in the presence of UV light) = 1-Chloropropane + 2-Chloropropane
a) Free radical substitution
b) Halogen exchange
c) Finkelstein reaction
d) Swarts reaction
Answer: a
Clarification: Free radical chlorination of alkanes give a mixture of isomeric haloalkanes which are difficult to separate. This reaction takes place in the presence of UV light or heat.

9. How many monohaloalkane isomers can be formed on the free radical bromination of (CH₃)₂CHCH₂CH₃?
a) 2
b) 3
c) 4
d) 5
Answer: c
Clarification: There are four different types of hydrogen atoms that can be replaced to give the following four isomers; (CH₃)₂CHCH₂CH₂Br, (CH₃)₂CHCH(Br)CH₃, (CH₃)₂C(Br)CH₂CH₃ and CH₃CH(CH₂Br)CH₂CH₃.

10. When propene reacts with HBr, two products are formed out of which one is predominates the other. Identify the minor product.
a) 1-Bromopropane
b) 2-Bromopropane
c) 1-Bromobutane
d) 2-Bromobutane
Answer: a
Clarification: According to Markovnikov’s rule, the negative part of the reagent (Br) attaches itself to the C atom with lesser number of hydrogen atoms. Hence, the Br attaches majorly to the second C atom of propane and forms 2-Bromopropane as the major product.

11. Which of the following is incorrect with regard to the reaction between C₂H₄ and Cl₂ in CCl₄?
a) It results in the formation of a vicinal dihalide
b) It results in the breaking of the C-C double bond
c) It results in the formation of a colourless compound
d) It results in the discharge of a reddish-brown colour

Answer: d
Clarification: The reddish-brown colour is discharged when Br₂ reacts with an alkene to form a vic-dihalide. This makes it an important test for the detection of a double bond.

12. The Finkelstein reaction takes place in what medium?
a) Concentrated HCl
b) Concentrated H₂SO₄
c) Dry acetone
d) Water
Answer: c
Clarification: When the alkyl bromide/chloride reacts with sodium iodide in dry acetone, the NaBr or NaCl formed gets precipitated in dry acetone. This facilitates the forward reaction according to Le Chatelier’s Principle.

13. What will be the product of the following reaction?

a)
b)
c)
d)
Answer: b
Clarification: This is a method of preparation of alkyl chloride from alchol by heating it with HCl. Only the alcoholic OH group will be substituted by Cl. The phenolic OH will reamain as it is.

14. The Finkelstein reaction can be used to prepare alkyl fluorides.
a) True
b) False
Answer: b
Clarification: The reagent in Finkelstein reaction is strictly sodium iodide which reacts with either alkyl bromides or chlorides to exchange the iodine with the other halogen group to form alkyl iodides.

15. Identify ‘X’ in the following reaction.

a) AgF
b) Hg₂F₂
c) CoF₂
d) SbF₃
Answer: b
Clarification: This is an example of Swarts reaction to prepare alkyl fluorides from alkyl bromides or chlorides. The main reagent is a metallic fluoride to exchange the F atom with the haloalkane.

Chemistry Multiple Choice Questions on “Ethers”.

1. Which of the following is the most suitable requirement for the dehydration of ethanol to form an ether?
a) Sulphuric acid at 413K
b) Sulphuric acid at 443K
c) Sodium hydroxide at 413K
d) Sodium hydroxide at 443K
Answer: a
Clarification: Alcohols undergo dehydration in the presence of protic acids to form either alkenes or ethers depending upon the reaction temperature conditions. At 413K, ethanol forms an ether with H₂SO₄.

2. Which of the following is not favourable for the proper dehydration of alcohol to form ether?
a) Good temperature control during reaction
b) Excess of alcohol
c) Presence of protic acids
d) Presence of bulky alkyl groups in the alcohol
Answer: d
Clarification: Secondary and tertiary alcohols give alkenes as major products during dehydration, because elimination competes over substitution. Hence, this method is mainly used for primary alcohols.

3. What is the major product formed when ethanol is dehydrated with concentrated H₂SO₄ at 413K?
a) Ethene
b) Methoxymethane
c) Methoxyethane
d) Ethoxyethane
Answer: d
Clarification: Symmetrical ethers are formed when alcohols are dehydrated with H₂SO₄ at controlled temperatures. This is an S_N2 reaction involving the attack of alcohol molecule on a protonated alcohol to give ethers.

4. Sodium methoxide on heating with bromoethane gives __________
a) methoxymethane
b) methoxyethane
c) ethoxyethane
d) diethyl ether
Answer: b
Clarification: This is an example of Williamson synthesis of unsymmetrical ether, where CH₃ONa is reacted with CH₃CH₂Br to form CH₃CH₂OCH₃, which is ethyl methyl ether.

5. The reaction between tert-Butyl chloride and sodium ethoxide gives _______
a) tert-Butyl ethyl ether
b) tert-Butyl methyl ether
c) 2-Methylprop-1-ene
d) butene
Answer: c
Clarification: The reactant sodium ethoxide is a strong nucleophile as well as a strong base, and hence elimination predominates over S_N2 to form alkene as a major product.

6. The boiling point of ethers is ______ the boiling point of alcohols of comparable molecular mass.
a) lower than
b) similar to
c) little higher than
d) much higher than
View Answer

Answer: a
Clarification: The large difference in boiling points of alcohols and ethers is due to the absence of intermolecular bonds in the latter.

7. Ethers are linear molecules with zero dipole moment.
a) True
b) False
Answer: b
Clarification: Ethers have angular structures due to the polar nature of C-O bond because of the difference in electronegativity of C and O atoms. Since the two C-O bonds are inclined to each other at about 110°, the dipole do not cancel out, and there is some dipole moment.

8. Ethoxyethane is insoluble in water as compared to butanol.
a) True
b) False
Answer: b
Clarification: Ethoxyethane and butanol have the same molecular mass and almost similar solubilities in water, i.e., 7.5g for ethoxyethane and 9g for butanol per 100ml of water. This is because of the fact that even ethers can form hydrogen bonds with water molecules just like the O of alcohols.

9. Which of the following is the least reactive functional group?
a) Alcohols
b) Ethers
c) Aldehydes
d) Ketones
Answer: b
Clarification: This is because the (-O-) group in ethers does not contain any active site as compared to for example, hydroxyl group (OH) in alcohols. However, they undergo C-O bond cleavage in drastic conditions.

10. One molecule of dialkyl ether produces how many molecules of alkyl halides with excess of halogen acid?
a) 1
b) 2
c) 3
d) 4
Answer: b
Clarification: Dialkyl ethers when treated with excess halogen acid first form an alkyl halide and alcohol. The alcohol further reacts with the excess acid to form the same alkyl halide and a water molecule. Thus, two alkyl halide molecules are produced in the end.

11. What product(s) are formed when the shown ether is heated with hydrogen iodide?

a) (C₆H₅)CH₂I and (C₆H₅)OH
b) (C₆H₅)CH₂OH and (C₆H₅)I
c) (C₆H₅)CH₂OH and (C₆H₅)CH₂I
d) (C₆H₅)OH and (C₆H₅)I
Answer: a
Clarification: The C-O bond of the phenol group is stronger than the C-O bond of the ether and alkyl aryl group. This is due to the partial double bond character because of sp² hybridised C-O cond. Therefore, the weaker C-O bond is broken and two major products, viz., phenol and iodomethyl benzene, are formed.

12. What is the major product of bromination of anisole in ethanoic acid?
a) o-Dibromobenzene
b) p-Dibromobenzene
c) o-Bromoanisole
d) p-Bromoanisole
Answer: d
Clarification: Phenyl alkyl ethers undergo bromination in the benzene ring with bromine in ethanoic acid. This due to the activation of benzene ring by OCH₃ group and its ortho, para directing effect. The para isomer is obtained in 90% yield.

13. Identify the major product of Friedel-Crafts acylation of anisole with ethanoyl chloride?
a) 2-Methoxytoluene
b) 4-Methoxytoluene
c) 2-Methoxyacetophenone
d) 4-Methoxyacetophenone
Answer: d
Clarification: Anisole undergoes Friedel-Crafts acylation where an acyl group is introduced at ortho and para position by reaction with acyl chloride with anhydrous AlCl₃ as catalyst. The para isomer will be the major product.

14. 4-Nitroanisole is obtained as the major product when anisole reacts with _____
a) concentrated H₂SO₄
b) concentrated HNO₃
c) mixture of concentrated H₂SO₄ and HNO₃
d) mixture of dilute H₂SO₄ and HNO₃
Answer: c
Clarification: Anisole undergoes nitration in the presence of concentrated acids H₂SO₄ and HNO₃ to yield a mixture of ortho and para nitroanisoles.

Chemistry Multiple Choice Questions on “Amines Classification”.

1. When two alkyl groups are attached to the nitrogen atom in an amine, it is known as a _______ amine.
a) primary
b) secondary
c) tertiary
d) aromatic
Answer: b
Clarification: Amines are classified as secondary or 2° when two of the hydrogen atoms of ammonia are replaced by an alkyl group and the third H remains attached as it is.

2. When only two hydrogen atoms are attached to the nitrogen of an amine, it is classified as a ________
amine.
a) primary
b) secondary
c) aliphatic
d) aromatic
Answer: a
Clarification: When an amine has two hydrogen atoms individually bonded to the nitrogen, it means that the third group is an alkyl or aryl substituent. This is called as a primary or 1° amine as only one H atom is replaced.

3. Which of the following is not a classification of amines?
a) Primary
b) Secondary
c) Tertiary
d) Quaternary
Answer: d
Clarification: Amines may be classified as primary, secondary or tertiary depending on whether 1, 2 or 3 hydrogen atoms of NH3 are replaced by alkyl/aryl groups respectively. Quaternary ammonium compounds are a different class of compounds where all four hydrogen atoms of ammonium salts are replaced by alkyl/aryl groups.

4. What is the most suitable classification of the following amine?

a) Secondary amine
b) Dialkyl amine
c) Tertiary amine
d) Aromatic amine
Answer: c
Clarification: This is trimethylamine, in which all the three hydrogen atoms are replaced by methyl (CH₃) groups. Hence, it is a tertiary or 3° amine.

5. Which of the following is a 2° amine?
a) CH₃CH₂NHCH₃
b) (CH₃)₃N
c) (CH₃CH₂CH₂)₂NCH₃
d) C₆H₅NH₂
Answer: a
Clarification: The three groups attached to CH₃CH₂NHCH₃ are one methyl group, one ethyl group and one hydrogen atom. This means that two of the hydrogen atoms are replaced and hence, it is a 2° or secondary amine.

6. Benzylamine is an aryl amine.
a) True
b) False
Answer: b
Clarification: Aryl amines are aromatic amines in which the nitrogen atom is directly bonded to the benzene ring. Whereas in benzylamine (C₆H₅CH₂NH₂), the nitrogen is attached to the side chain of the aromatic ring. Hence, it is an arylalkyl amine.

7. Which of the following is the most suitable classification for C₆H₅NHCH₃?
a) Tertiary amine
b) Aliphatic amine
c) Arylalkyl amine
d) Mixed amine

Answer: d
Clarification: In the given amine, there are two substituents, one methyl group and one phenyl group. Hence, it is a secondary aryl amine and since both the substituent groups are different, it is a mixed amine.

8. Which of the following is an arylalkyl amine?
a) C₆H₅NHC₆H₅
b) C₆H₅NH₂
c) (C₆H₅CH₂)NH
d) (C₆H₅)₃N
Answer: c
Clarification: Arylalkyl amines are aromatic amines which are side chain substituted, i.e., the nitrogen is not directly attached to the phenyl group but to a side chain of the benzene ring. In (C₆H₅CH₂)NH, there are two same groups attached to the nitrogen where it is attached to a benzyl carbon, instead of an aryl carbon.

9. Which of the following categories does CH₃-NH-CH₃ not belong to?
a) Secondary amine
b) Simple amine
c) Aliphatic amine
d) Mixed amine
Answer: d
Clarification: There are two hydrogen that replaced by CH₃ group, making it a secondary amine and since both the replacing groups are identical, it is a simple amine. Also, it is aliphatic in nature as both the substituents are alkyl groups.

10. Aromatic amines cannot have an alkyl group attached to N atom.
a) True
b) False
Answer: b
Clarification: There can be an alkyl group attached to an aromatic amine, but at least one of the substituents should be a phenyl group in aryl amine. For arylalkyl amines (which are also aromatic), the benzene ring is not directly linked to the nitrogen.

11. (C₃H₇)N(CH₃)(C₂H₅) is not a ________ amine.
a) secondary
b) tertiary
c) aliphatic
d) mixed
Answer: a
Clarification: In the given amine, all the three hydrogens of NH₃ are replaced by one each of propyl, ethyl and methyl groups, and is a tertiary or 3° amine. Since all the three groups are alkyl and different, it is an aliphatic mixed amine.

12. The compound shown is a _______ amine.

a) 1° aryl
b) 1° arylalkyl
c) 2° aryl
d) 2° arylalkyl
Answer: a
Clarification: Only one hydrogen atom is replaced by an aromatic group, in which the nitrogen is directly linked to the sp² hybridised carbon of benzene ring. Hence, it is a primary aromatic aryl amine.

13. Which of the following best describes the amine (CH₃CH₂)₃N?
a) Secondary, simple
b) Secondary, mixed
c) Tertiary, simple
d) Tertiary, mixed
Answer: c
Clarification: All the three hydrogen atoms of ammonia are replaced by the same ethyl group in (CH₃CH₂)₃N, which makes is a 3° simple amine.

14. Which of the following is a primary arylalkyl amine?
a) CH₃NH₂
b) C₆H₅CH₂NH₂
c) C₆H₅NH₂
d) (C₆H₅)₂NH
Answer: b
Clarification: Since it should be primary, it should have an alkyl/aryl group attached to the NH₂ molecule, and because it is arylalkyl, the nitrogen should be linked to an sp³ hybridised benzyl carbon rather than to an aryl carbon.

15. The compound CH₃NHC₆H₅ is a ______ amine.
a) aliphatic simple
b) aliphatic mixed
c) aromatic simple
d) aromatic mixed
Answer: d
Clarification: Since the compound consists of a benzene ring, it invariably is an aromatic amine. Moreover, it also contains an alkyl methyl group beside the phenyl group and this makes it a mixed amine.

Chemistry Multiple Choice Questions on “Biomolecules Carbohydrates – 1”.

1. Which of the following carbohydrates does not satisfy the formula C_x(H₂O)_y?
a) Fructose
b) Glucose
c) Deoxyribose
d) Lactose
Answer: c
Clarification: Initially, most of the carbohydrates had the general formula C_x(H₂O)_y. Later on it was found out that few of the compounds either fit into this formula but were not carbohydrates or they did not conform to this formula but were hydrates of carbon.

2. Which of the following carbohydrates does not have the formula C₁₂H₂₂O₁₁?
a) Galactose
b) Sucrose
c) Allolactose
d) Maltose
Answer: a
Clarification: Galactose is a monosaccharide with the formula C₆H₁₂O₆. Sucrose, allolactose and maltose are disaccharides with the same chemical formula C₁₂H₂₂O₁₁.

3. The compound with the formula C₂(H₂O)₂ is a ______
a) carbohydrate
b) carboxylic acid
c) aldehyde
d) monosaccharide
Answer: b
Clarification: The compound is acetic acid (CH₃COOH). Even though it has the general formula C_x(H₂O)_y of carbohydrates, it is not one. This is one the flaws of the general formula definition of carbohydrates.

4. Identify the correct formula for the carbohydrate rhamnose?
a) C₅H₁₀O₅
b) C₆H₁₂O₅
c) C₆H₁₂O₆
d) C₁₂H₂₂O₁₁
Answer: b
Clarification: Rhamnose is an example of a carbohydrate that does not satisfy the general formula C_x(H₂O)_y. Its formula is C₆H₁₂O₅.

5. Which of the following class of compounds is not a part of the large group of carbohydrates?
a) Polyamino aldehydes
b) Polyhalo aldehydes
c) Polyhydroxy ketones
d) Polyhydroxy carboxylic acids
Answer: c
Clarification: Polyamino aldehydes and polyhalo aldehydes do not contain an OH group. Polyhydroxy carboxylic acids do not contain a CHO or a keto group. These also do not produce OH substituted compounds on hydrolysis.

6. Which of the following carbohydrates is not a sugar?
a) Glucose
b) Fructose
c) Lactose
d) Cellulose
Answer: d
Clarification: Glucose, fructose and lactose are examples of compounds that are sweet in taste and are called sugars. Cellulose is a non-sugar that is tasteless, water insoluble and amorphous.

7. Which of the following is not a polysaccharide?
a) Cellulose
b) Stachyose
c) Starch
d) Glycogen
Answer: b
Clarification: Polysaccharides are those carbohydrates which yield a very large number of monosaccharide units (>10) on hydrolysis. Stachyose (C₂₄H₄₂O₂₁) is a tetrasaccharide that gives four monosaccharide units on hydrolysis.

8. Identify the monosaccharide from the following.
a) Deoxyribose
b) Sucrose
c) Maltose
d) Fructose
Answer: a
Clarification: Monosaccharides are the simplest carbohydrates which cannot be hydrolysed into simpler units. Deoxyribose (C₅H₁₀O₄) is a monosaccharide.

9. Raffinose is an example of a ________
a) monosaccharide
b) disaccharide
c) trisaccharide
d) tetrasaccharide
Answer: c
Clarification: Raffinose (C₁₈H₃₂O₁₆) is an oligosaccharide which on hydrolysis gives three different monosaccharides, galactose, glucose and fructose. Hence, it is a trisaccharide.

10. Which of the following disaccharides gives two same monosaccharide units on hydrolysis?
a) Maltose
b) Sucrose
c) Lactose
d) Lactulose
Answer: a
Clarification: When any carbohydrate undergoes hydrolysis and produces two separate units of monosaccharides, it is a disaccharide. The used units that are produced may be same. Maltose on hydrolysis gives two units of glucose itself.

11. Sucrose consists of which of the following monosaccharide units?
a) Fructose, galactose
b) Fructose, glucose
c) Galactose, glucose
d) Glucose, glucose
Answer: b
Clarification: Sucrose is a disaccharide, also known as common sugar, composed of two different monosaccharide units, glucose and fructose, which are obtained on hydrolysis.

12. Which of the following disaccharides does not consist of two glucose units?
a) Trehalose
b) Cellobiose
c) Isomaltose
d) Lactulose
Answer: d
Clarification: Lactulose is a disaccharide which is composed of two different monosaccharide units namely, galactose and fructose. Whereas trehalose, cellobiose and isomaltose are disaccharides consisting of two glucose units.

13. All monosaccharides are reducing sugars.
a) True
b) False
Answer: a
Clarification: All monosaccharides whether aldose or ketose, are reducing sugars. This is because they have an aldehyde group or can tautomerize in solution to form an aldehyde group, which reduces Fehling’s solution and Tollen’s reagent.

14. Which of the following is a non-reducing sugar?
a) Galactose
b) Glucose
c) Fructose
d) Sucrose
Answer: d
Clarification: Sucrose is a non-reducing disaccharide which cannot convert to an open chain with a free aldehyde group and hence cannot reduce Fehling’s solution and Tollen’s reagent.

15. Glucose is an aldohexose.
a) True
b) False
Answer: a
Clarification: Glucose is an aldehydic carbohydrate (with CHO) group at end of chain) with six carbon atoms (hexose). Its formula is C₆H₁₂O₆.

Chemistry Multiple Choice Questions on “Drugs and their Classification”.

1. A chemical compound that affects human metabolism and provides cure from diseases is called ______
a) poison
b) medicine
c) enzyme
d) hormone
Answer: b
Clarification: The chemical compounds which interact with specific targets and initiate a biological response in the body are called drugs. When the response is therapeutic and useful, they are called medicines and when it is harmful, they are called poisons.

2. Which of the following is not a classification of drugs?
a) Based on size
b) Based on chemical structure
c) Based on drug action
d) Based on target
Answer: a
Clarification: Drugs are mainly classified on the basis of four criteria, namely pharmacological effect, drug action, chemical structure and molecular targets in the body.

3. The classification of drugs based on ______ is the most useful one for medicinal chemists.
a) pharmacological effect
b) drug action
c) chemical structure
d) molecular targets
Answer: d
Clarification: Medicinal chemists are interested in the location at which a particular drug will create action and assign specific drugs to people based on the requirements. This also involves the mechanism of drug action on target based on structure.

4. Identify the compound which does not act as a target for drug action in the human body?
a) RNA
b) DNA
c) Vitamin C
d) Protein
Answer: c
Clarification: The usual macromolecular targets of drugs in the body are carbohydrates, lipids, proteins and nucleic acids. Since vitamins are not produced by the body, they can be controlled without the use of drugs.

5. Which of the following drugs is not classified in the criteria based on the pharmacological effect?
a) Antihistamines
b) Antiseptics
c) Analgesics
d) Antipyretics
View Answer

Answer: a
Clarification: Pharmacological effects of drugs provides a wide range of drugs that have a same effect on a specific type of problem. Analgesics have pain killing effect, antiseptics prevent the growth of microbes and antipyretics help in lowering body temperature during fever.