Which is not the true statement about $KMnO_4$?

Which of the following decolourises the colour of acidic $KMnO_4$?

Assign $A, B, C, D$ from the given type of reaction.
$Pb(NO_3)_2 + 2NaOH \longrightarrow Pb(OH)_2 \downarrow + 2NaNO_3$

When an acidic solution of $K_2Cr_2O_7$ is added to $Na_2SO_3$,it turns green. Which of the following compounds is formed in this reaction?

Given below are two statements :-
Statement $I$ :- In redox titration,the indicators used are sensitive to change in $pH$ of the solution.
Statement $II$ :- In acid-base titration,the indicators used are sensitive to change in oxidation potential.
In the light of the above statements,choose the most appropriate answer from the options given below.

Assign $A, B, C, D$ from the given type of reaction.
$K_2Cr_2O_7 + 2NaOH \longrightarrow 2K_2CrO_4 + H_2O$
Identify the nature of the product $CrO_4^{2-}$ formed in the reaction.