a) Azotan(V) wapnia - $Ca{\left(N{O}_3\right)}_2$  

$Ca{\left(OH\right)}_2+2HN{O}_3\to Ca{\left(N{O}_3\right)}_2+2H_{2}O$

$Ca+2HN{O}_3\to Ca{\left(N{O}_3\right)}_2+H_2\uparrow$  

$Ca{\left(OH\right)}_2+N_2{O}_5\to Ca{\left(N{O}_3\right)}_2+H_{2}O$