Study the reaction given below and answer the questions that follow:
\mathrm{NaNO_3 + H_2SO_4\ (Conc.)} \xrightarrow{<\;200^\circ\mathrm{C}} \mathrm{NaHSO_4 + HNO_3}(a) Give one reason for maintaining the temperature below 200°C.
(b) Why is concentrated Sulphuric acid used in the above reaction?
(a) The temperature is maintained below 200°C because nitric acid decomposes at higher temperature to give nitrogen dioxide, water and oxygen.
4HNO3 ⟶ 4NO2 + 2H2O + O2
(b) Concentrated sulphuric acid is used because it is a non-volatile acid with a high boiling point. It displaces the more volatile nitric acid from sodium nitrate and does not distil over with nitric acid vapours.
More ICSE Moderate level questions
Carbon reacts with an acid to form carbon dioxide, water and nitrogen dioxide. (a) Name the acid used in the reaction. (b) Write a balanced chemical equation for the reaction that occurs.
Anil is a laboratory assistant in a college. He prepared nitric acid but stored it in a transparent container exposed to sunlight. After a few days, brown fumes were observed in the container and the acid turned slightly yellowish in colour. (a) What was the error made by Anil while storing the acid? (b) Why were brown fumes observed in the container? (c) How can the yellowish tinge in the acid be removed?
Complete the following sentences by choosing the correct option from the brackets: (a) The oxide that dissolves in caustic potash (KOH) is ............... . [ZnO / CuO] (b) The reaction that takes place at the anode during the electrolysis of molten lead bromide is ............... . [2Br − 2e− ⟶ 2Br− / 2Br− − 2e− ⟶ Br2] (c) The volume occupied by 8 grams of oxygen gas at STP is ............... litres. [5.6 / 8.96] [Atomic weight of O = 16] (d) ............... does not give hydrogen gas when it reacts with cold and very dilute nitric acid. [Cu / Mn] (e) ............... is a polar covalent compound. [HCl / CCl4]
Seema added a few pieces of copper turnings to a test tube containing concentrated acid P and she noticed that a reddish-brown gas evolved. (a) Name the acid P used by Seema. (b) Write a balanced chemical equation for the reaction that took place.
Complete and balance the following equations: (a) NH4Cl + Ca(OH)2 → (b) CuSO4 + NH4OH → (c) Cu + Conc. HNO3 →
Give one significant observation when: (a) Barium chloride solution is added to zinc sulphate solution. (b) Lead nitrate is heated strongly. (c) Chlorine gas is passed through moist starch iodide paper.
Give balanced equations for the following: (a) Action of dilute hydrochloric acid on ammonium carbonate. (b) Oxidation of sulphur with hot concentrated nitric acid. (c) Reaction of concentrated sulphuric acid with carbon.
Name the gas produced during each of the following reactions: (a) When copper is treated with hot, concentrated nitric acid. (b) When ammonia is burnt in an atmosphere of oxygen. (c) When ferrous sulphide reacts with dilute hydrochloric acid.
Give balanced equations for the following: (a) Copper reacts with concentrated Nitric acid. (b) Aluminium nitride is treated with warm water.
The nitrate which on thermal decomposition leaves behind a residue which is yellow when hot and white when cold: (a) Lead nitrate (b) Ammonium nitrate (c) Copper nitrate (d) Zinc nitrate
The salt formed when concentrated sulphuric acid reacts with KNO3 above 200°C: (a) K2SO4 (b) K2SO3 (c) KHSO4 (d) KHSO3
State whether the following statements are True or False: (a) Organic compounds having different molecular formula, but same structural formula are called isomers. (b) A salt is a compound formed by partial or complete replacement of the hydrogen ion of an acid by a metal or electropositive ion.
