Lithium doesn't form Alum

Question

$\begin{array}{1 1}(a)\;It\;is\;solid,and\;hard\;nature\\(b)\;It\;is\;a\;gas,and\;easily\;diffusion\\(c)\;Due\;to\;large\;size\\(d)\;Due\;to\;large\;size\end{array}$