BeO reacts with HF in presence of ammonia to give A which on thermal decomposition produces B and ammonium fluoride. Oxidation state of Be in A is

Step-by-step solution

BeO on reaction with HF in the presence of ammonia, NH 4 2 BeF 4 is formed which on heating forms BeF 2 along with ammonium fluoride. BeO + 2 NH 3 + 4 HF → NH 4 2 BeF 4 + H 2 O Compound A , is NH 4 2 BeF 4 NH 4 2 BeF 4 → heat BeF 2 + 2 NH 4 F Compound B is BeF 2 In NH 4 2 BeF 4 the oxidation state of Be is + 2 .