Answer
a) $CaH_2+2H_2O \rightarrow Ca(OH)_2+2H_2$
b) $AlH_3+3H_2O \rightarrow Al(OH)_3+3H_2$
c) $NaH+H_2O \rightarrow NaOH+H_2$
Work Step by Step
When metal hydrides react with water, hydrogen is obtained:
a) $CaH_2+2H_2O \rightarrow Ca(OH)_2+2H_2$
b) $AlH_3+3H_2O \rightarrow Al(OH)_3+3H_2$
c) $NaH+H_2O \rightarrow NaOH+H_2$