Which of the following hydrides is electron-deficient?

Which of the following statement$(s)$ is/are correct:
$A$. $NaH$ is a non-volatile hydride
$B$. $MgH_2$ is a polymeric hydride
$C$. $NH_3$ is an electron-precise hydride
$D$. $H_2O$ is an electron-rich hydride

Which of the following pairs will not produce dihydrogen gas?

Sulfuric acid has a strong affinity for water because,

Which of the following statements is correct?

Identify the incorrect statement.