Write the conditions to maximise the yield of H 2 SO 4 by contact process.

The key step to maximise the yield of H 2 SO 4 is the oxidation of SO 2 to SO 3 in presence of V 2 O 5 catalyst. 2 SO 2 g + O 2 g ⇌ V 2 O 5 2 SO 3 g ; ∆ H ° = - 196 . 6 kJ mol - 1 The above reaction is exothermic, reversible and the forward reaction leads to a decrease in volume. So, in accordance with Le Chatelier's principle, low temperature and high pressure are the favourable conditions for maximum yield. But the temperature should not be too low since the rate of reaction will become slow. The optimum conditions in the contact process to maximise the yield of sulphuric acid in an industrial plant is a pressure of 2 bar and temperature around 720 K .

Write the reactions of F 2 and Cl 2 with water.

When chlorine gas reacts with water, it gives hydrochloric acid and hypochlorous acid. Cl 2 g Chlorine + H 2 O l Water → HCl aq Hydrochloric acid + HOCl aq Hypochlorous acid Fluorine gas on reaction with water gives hydrogen ions, fluoride ions, oxygen gas as products. 2 F 2 g + 2 H 2 O l → 4 H + aq + 4 F - aq + O 2 g

ClF 3 exists but FCl 3 does not exist. Why?

ClF 3 exists because chlorine is a period 3 element and has vacant d -orbitals, due to which it can easily expand its octet. Fluorine on the other hand is a period 2 element and has no d -orbitals to expand its octet and form bond with three chlorine atoms to form FCl 3 .