Answer
See answer below.
Work Step by Step
a) $CO_2(g)+2\ NH_3(g)\rightarrow NH_2CONH_2(s)+H_2O(l)$
b) $UO_2(s)+4\ HF(aq)\rightarrow UF_4(s)+2\ H_2O(l)$
$UF_4(s)+F_2(g)\rightarrow UF_6(s)$
c) $TiO_2(s)+2\ Cl_2(g)+2\ C(s)\rightarrow TiCl_4(l)+2\ CO(g)$
$TiCl_4(l)+2\ Mg(s)\rightarrow Ti(s)+2\ MgCl_2(s)$
