Oxalic acid when treated with potassium permanganate in the presence of an acid,produces

The sodium salt of an organic acid $'X'$ produces effervescence with conc. $H_2SO_4$. $'X'$ reacts with an acidified aqueous $CaCl_2$ solution to give a white precipitate which decolourises an acidic solution of $KMnO_4$. $'X'$ is:

Which of the following will not change the orange colour of $K_2Cr_2O_7$ into green colour in an acidic medium?

Match List-$I$ with the List-$II$.

List-$I$ (Reaction)	List-$II$ (Type of redox reaction)
$A$. $N_{2(g)} + O_{2(g)} \rightarrow 2 NO_{(g)}$	$I$. Decomposition
$B$. $2 Pb(NO_3)_{2(s)} \rightarrow 2 PbO_{(s)} + 4 NO_{2(g)} + O_{2(g)}$	$II$. Displacement
$C$. $2 Na_{(s)} + 2 H_2 O_{(l)} \rightarrow 2 NaOH_{(aq)} + H_{2(g)}$	$III$. Disproportionation
$D$. $2 NO_{2(g)} + 2 OH^-_{(aq)} \rightarrow NO^-_{2(aq)} + NO^-_{3(aq)} + H_2 O_{(l)}$	$IV$. Combination

Choose the correct answer from the options given below:

Which of the following compounds does not produce a green-coloured product on thermal decomposition?

$A$ solution of colourless salt $H$ on boiling with excess $NaOH$ produces a non-flammable gas. The gas evolution ceases after sometime. Upon addition of $Zn$ dust to the same solution,the gas evolution restarts. The colourless salt$(s)$ $H$ is (are):