JEE Main · 2023 · 24 Jan 2023 · Shift 1 · s-Block Elements

Reaction of BeO with ammonia and hydrogen fluoride gives 'A' which on thermal decomposition gives

BeF_{2}

and

NH_{4} F

. What is 'A' ?

Answer: (A)

Solution

Beryllium oxide treated with ammonia and hydrogen fluoride gives ammonium tetrafluoroberyllate,

(N H_{4})_{2} Be F_{4}

, in which the

Be F_{4}^{2 -}

ion is balanced by two ammonium ions. On heating it loses ammonium fluoride and leaves beryllium difluoride,

(N H_{4})_{2} Be F_{4} Δ Be F_{2} + 2 N H_{4} F

, matching the stated products. Compound A is ammonium tetrafluoroberyllate.

JEE Main · 2023 · 24 Jan 2023 · Shift 1 · Single correct option