250+ TOP MCQs on Hydrogen – Water and Answers

Chemistry Multiple Choice Questions on “Hydrogen – Water”.

1. Water is amphoteric in nature.
a) true
b) false
Answer: a
Clarification: Yes, the above statement is true because water is amphoteric in nature. It acts as an acid when it is with a strong base and acts as a base when it is with strong acid. It is an oxidizing as well as a reducing agent.

2. Water reacts with ________________
a) metalloids
b) metals only
c) nonmetals only
d) both metals and nonmetals
Answer: d
Clarification: In redox reactions, water reacts with metals and nonmetals both. For example, take the reaction of sodium with water, the products are sodium hydroxide and hydrogen, whereas fluorine reacts with water in order to form hydrogen cation and fluorine anion with oxygen.

3. Water is of how many types in hydrated salt?
a) 1
b) 5
c) 4
d) 3
Answer: b
Clarification: In hydrated salt, there are five types of water. The five types of water in hydrated salt are i. coordinated water, ii. hydrogen bonded water, iii. lattice water, iv. clathrate water and v. zeolite water.

4. Compounds can undergo hydrolysis with water.
a) false
b) true
Answer: b
Clarification: Yes, a number of compounds such as calcium hydride(CaH), calcium phosphide(Ca₃PO₄), etc can undergo hydrolysis with water. Therefore we can say that compounds can undergo hydrolysis with water.

5. Do ice float on Water?
a) may be
b) yes
c) cannot say
d) no
Answer: b
Clarification: Ice floats on water, this is because of the density of ice i.e. mass per unit volume (density of ice is 0.9167 g/cm³ and density of water is 1g/cm³) is lesser than that of water. This is the reason, ice floats over water.

6. The type of hardness that occurs due to the presence of bicarbonate of calcium and magnesium ions hardness is _______________
a) half hardness
b) temporary hardness
c) permanent hardness
d) momentary hardness
Answer: b
Clarification: The water which forms come with soap is known as hard water. The hardness that occurs due to the presence of bicarbonates of calcium and magnesium is temporary hardness. Temporary hardness can be removed by boiling and Clark’s process.

7. What is the most efficient method to get water with zero degrees hardness?
a) Electrolysis
b) Permutit process
c) Synthetic resins
d) Calgon process
Answer: b
Clarification: Permutit is hydrated sodium aluminum silicate, it exchanges it’s sodium ions for divalent ions of calcium and magnesium, permutit when fully exhausted can be regenerated by treating with 10% of sodium chloride solution. It is the most efficient method to get water with zero degrees of hardness.

8. Which of the following is a method of removing temporary hardness?
a) boiling
b) adding washing soda
c) adding caustic soda
d) adding sodium phosphate
Answer: a
Clarification: The methods that are used for removing the temporary hardness of water are by boiling and by Clark’s process. Adding washing soda, caustic soda and sodium phosphates are for permanent hardness removal.

9. What is Calgon?
a) potassium Phantom metaphosphate
b) sodium penta metaphosphate
c) potassium hexametaphosphate
d) sodium hexametaphosphate
Answer: d
Clarification: Permanent hardness is removed by Calgon process. In this process, Calgon is referred to Sodium hexametaphosphate and its chemical formula is given by Na₆P₆O₁₈. This Calgon when added to hard water forms soluble complex.

10. Which of the following, do you think are the synthetic resins present in removal of permanent hardness?
a) cation exchange resins only
b) anion exchange resins only
c) both cation exchange resins and anion exchange resins
d) neither cation exchange resins nor anion exchange resins
Answer: c
Clarification: There are two types of synthetic resins used for removal of permanent hardness. They are cation exchange resins which are big molecules containing sulfonic acid group and an anion exchange resins which are also big molecules containing amino acids.

11. What is the hybridization of water?
a) spd
b) sp³
c) sp²
d) sp
Answer: b
Clarification: Water has a hybridization of sp³. In a water molecule oxygen has two lone pairs and two bonded hydrogens. Its structure is V in shape and has a bent structure. Water has a chemical formula of H₂O.

12. Pure water is a good conductor.
a) true
b) false
Answer: b
Clarification: As pure water is not a good conductor, we add a little amount of an acid or alkali or salt in order to make it a good conductor. The above-given statement that pure water is a good conductor, is considered to be false.

13. Water has a maximum density at _____ degree centigrade.
a) 32
b) 100
c) 0
d) 4
Answer: d
Clarification: Water has a maximum density at 4-degree centigrade, this is because at 4-degree centigrade, as opposite forces are in balance that is like the formation of Ice and maintaining of the liquid phase of water. Any less than 4-degree centigrade or greater than 4-degree centigrade, the water density is lesser than that of 4-degree centigrade.

14. Dielectric constant of water is ____________
a) 1
b) higher
c) 0
d) lower
Answer: b
Clarification: Water has a high dielectric constant and that is 78.39. The interaction of water with ionic substances is effective along with the release of energy in a noted quantity because of the Ion dipole interaction. This is applicable to the intercations with polar substances also.

15. Urea’s dissolution is because of __________
a) carbon bond
b) oxygen Bond
c) hydrogen bond
d) nitrogen bond
Answer: c
Clarification: The dissolution of covalent compounds like urea, glucose, and ethanol is due to the tendency of these molecules to form a hydrogen bond with water. Urea’s dissolution as because of the hydrogen bond.