Chemistry Multiple Choice Questions on “P-Block Elements – Sulphuric Acid”.
1. What is the first step involved in forming sulphuric acid through contact process?
a) Conversion of SO2 to SO3
b) Burning of Sulphur or roasting sulphide ores to generate SO2
c) Absorption of SO3 in sulphuric acid
d) Purifying SO3
Answer: b
Clarification: The first step involved in forming sulphuric acid through contact process is Burning of Sulphur or roasting sulphides ores to generate SO2. Sulphur dioxide is purified by removing dust and arsenic impurities.
2. In contact process, arsenic impurity has to be removed before proceeding.
a) True
b) False
Answer: a
Clarification: Sulphur dioxide is purified by removing dust and arsenic impurities. Arsenic is a catalyst poison for vanadium pentoxide catalyst. Hence, it has to be removed completely before entering into the catalytic chamber.
3. What is the catalyst used in contact process in the conversion of Sulphur dioxide to Sulphur trioxide?
a) Finely divided iron
b) Molybdenum
c) Vanadium pentoxide
d) Platinum
Answer: c
Clarification: After burning Sulphur in the presence of oxygen the formed Sulphur dioxide needs to be reacted with oxygen to form Sulphur trioxide. It is an exothermic reaction and vanadium pentoxide is used as the catalyst.
4. Sulphuric acid is called the ‘King of Acids’.
a) True
b) False
Answer: a
Clarification: Even though hydrogen iodide is stronger sulphuric acid is called the ‘King of Acids’. All acids can be formed from sulphuric acid, because of its low volatility, it can be used to manufacture more volatile acids from their corresponding salts.
5. Which of the following is not a property of sulphuric acid?
a) It acts as a strong dehydrating agent
b) It is a Lewis acid
c) It cannot char carbohydrates
d) It is dense and oily
Answer: c
Clarification: Sulphuric acid is a Lewis acid and is a dense oily liquid which acts as a strong dehydrating agent due to its high affinity towards water. It chars carbohydrates to from black precipitates of carbon.
6. Which process is used for large scale manufacturing of sulphuric acid?
a) Haber’s process
b) Ostwald’s process
c) Smith’s process
d) Contact process
Answer: d
Clarification: These days sulphuric acid is mostly prepared by the Contact process. The acid produced by this method is free from arsenic impurities and hence can be safely used for the preparation of edible products.
7. What is the hybridization of Sulphur in sulphuric acid?
a) sp
b) sp2
c) sp3
d) It is not hybridized
Answer: c
Clarification: The hybridization of Sulphur in sulphuric acid is sp3 and is tetrahedral shaped. The structure is often drawn with two double bonds, with double bond formed from d-orbitals on Sulphur and p-orbitals on oxygen.
8. What are the favorable conditions for maximum yield of Sulphur trioxide?
a) High pressure, low temperature, excess of oxygen
b) High pressure, low temperature, less oxygen
c) Low pressure, low temperature, excess of oxygen
d) High pressure, high temperature, excess of oxygen
Answer: a
Clarification: High pressure is preferred since the forward reaction proceeds with decrease in number of moles. Low temperature is preferred because the reaction is highly exothermic and to have maximum yield of Sulphur trioxide, oxygen is used in excess.
9. What happens in the purifying chamber in contact process?
a) The compounds are washed with nitrogen
b) Dust particles are removed
c) A spray of HCl is used for drying gasses
d) The compounds are heated
Answer: b
Clarification: In the purifying unit the dust particles are removed by blowing steam and the soluble impurities are removed by washing the gases with water. A spray of conc. Sulphuric acid is used for drying gasses.
10. Which of the following is true about sulphuric acid?
a) It is a soapy liquid
b) It is a monobasic acid
c) It is a dibasic acid
d) It is a tribasic acid
Answer: c
Clarification: Sulphuric acid is an oily liquid and is dibasic in nature. It is a dibasic acid because it contains two hydrogen atoms which ionize in aqueous solution to become hydrogen ions. When it reacts with bases like sodium hydroxide it form two kinds of salts proving its dibasic nature.