$\begin{array}{1 1} \text{a. All metal carbonates react with acid to give a salt, water and carbon dioxide} \\ \text{
b. All metal oxides react with water to give salt and acid} \\ \text{
c. Some metals react with acids to give salt and hydrogen} \\ \text{
d. Some non metal oxides react with water to form an acid}
\end{array} $
