Which of the following statements is correct for $PH_3$?

Which of the following statements are correct about the reaction between the copper metal and dilute $HNO_3$?
$(I)$ The principal reducing product is $NO$ gas.
$(II)$ $Cu$ metal is oxidised to $Cu^{2+}$ (aq.) ion which is blue in colour.
$(III)$ $NO$ is paramagnetic and has one unpaired electron in antibonding molecular orbital.
$(IV)$ $NO$ reacts with $O_2$ to produce $NO_2$ which is linear in shape.
Choose the correct statements.

Give the disproportionation reaction of $H_3PO_3$.

Which of the following acids forms three series of salts?

Which substance is used as a smoke screen in warfare?

$p$-Block elements form acidic,basic,and amphoteric oxides. Explain each property by giving two examples and also write the reactions of these oxides with water.