$Cu +$ conc. $HNO_3$ (hot) $\rightarrow Cu(NO_3)_2 + X$ (oxide of nitrogen);
then $X$ is

The number of bridged oxygen atoms present in compound $B$ formed from the following reactions is
$Pb(NO_3)_2 \xrightarrow{673 \ K} A + PbO + O_2$
$A \xrightarrow{\text{Dimerise}} B$

Which gas is formed in the atmosphere due to lightning?

Which of the following is the strongest Lewis base?

Which oxide is alkaline?

$P_4O_{10}$ cannot be used to dry $NH_3$ because ..............