Which statements about nitrite are correct?

ANitrite decolourises acidified $KMnO X_{4}$ , the nitrogen being oxidised from $+ 3$ to $+ 5$
BNitrite with dilute acid gives a gas that turns lime water milky
CIn acetic acid medium nitrite liberates iodine from potassium iodide, turning starch blue
DWarming $NaNO X_{2}$ with dilute $H X_{2} SO X_{4}$ gives colourless $NO$ that turns brown in air

Answer: A, C, D

Nitrous acid disproportionates to

NO

, which reacts with

O X_{2}

to give

NO X_{2}

(first statement). Nitrite oxidises

I X^{-}

I X_{2}

giving the blue starch complex, and is itself oxidised to nitrate by permanganate (

+ 3

+ 5

). The nitrogen oxides evolved do not give milky lime water; that behaviour belongs to

CO X_{2}

and

SO X_{2}