When $SO_2$ gas is passed through an acidic solution of $K_2Cr_2O_7$,what is the change in the oxidation state of chromium?

Which type of reaction occurs in Kolbe's electrolysis? Why?

$A$ solution of $Na_2S_2O_3$ is standardized iodometrically against $0.167 \ g$ of $KBrO_3$ where $BrO_3^-$ changes to $Br^-$. This process requires $45 \ mL$ of the $Na_2S_2O_3$ solution. What is the strength of the $Na_2S_2O_3$ in $N$?
$[Mw \text{ of } KBrO_3 = 167]$

Consider the following redox reaction taking place in acidic medium: $BH_{4}^{-}(aq) + ClO_{3}^{-}(aq) \rightarrow H_{2}BO_{3}^{-}(aq) + Cl^{-}(aq)$. If the Nernst equation for the above balanced reaction is $E_{cell} = E_{cell}^{o} - \frac{RT}{nF} \ln Q$, then the value of $n$ is . . . . . . . (Nearest integer)

$KMnO_4$ reacts with $H_2O_2$ in an acidic medium. The number of moles of oxygen produced per mole of $KMnO_4$ is

Phenolphthalein does not act as an indicator for the titration between