When $KMnO_4$ solution is titrated with a solution containing $Fe^{2+}$ ions,the indicator used in this titration is

Which of the following reactions is not a redox reaction?

Number of moles of $MnO_4^{-}$ required to oxidise one mole of ferrous oxalate completely in acidic medium will be $:-$ (in $mole$)

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$SrCrO_4 \downarrow + 2AcOH \text{ (Excess)} \longrightarrow Sr(AcO)_2 + H_2Cr_2O_7$

Upon the addition of a solution $A$ to a strongly acidified solution of barium nitrate,a white precipitate was obtained which did not dissolve even after large addition of water. Solution $A$ contained

In the reaction of gold with aqua regia,the oxidation state of Nitrogen changes from