Question

$BeO$ 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 _______

Answer 1

$BeO+2NH_3+4HF⟶(NH_4)_2 [BeF_4]$
$(A)$

$(NH_4)_2(BeF_4)\xrightarrow{Heating} BeF_2+2NH_4F$
$(B)$

Oxidation State of $Be$ in $(A)$ is $(+2)$