When $KMn{O}_4$ solution is added to oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time because

1.  $C{O}_2$ is formed as the product

2.  Reaction is exothermic

3.  $Mn{O}_4^{-}$ catalyses the reaction

4.  $M{n}^{2+}$ acts as autocatalyst

There are 14 elements in the actinoid series. Which of the following elements does not belong to this series?

$KMn{O}_4$ acts as an oxidizing agent in an acidic medium. The number of moles of $KMn{O}_4$ that will be needed to react with one mole of sulphide ions in an acidic solution is$\mathrm{:}$

Which of the following is amphoteric oxide ?

Gadolinium (atomic number 64) is an element of the 4f series, Identify the correct electronic configuration of gadolinium from the following options:

\(1. (X e) 4 f^{7} 5 d^{1} 6 s^{2} \)

2. \( (X e) 4 f^{6} 5 d^{2} 6 s^{2}\)

3. \((X e) 4 f^{8} 6 d^{2}\)

4. \((X e) 4 f^{9} 5 s^{1}\)

Interstitial compounds are formed when small atoms are trapped inside the crystal lattice of metals. Which of the following is not the characteristic property of interstitial compounds? 

The magnetic moment is associated with its spin angular momentum and orbital angular momentum. Determine the spin only magnetic moment value of $C{r}^{3+}$ ion:

KMnO₄ acts as an oxidising agent in alkaline medium. When alkaline KMnO₄ is treated with KI, iodide ion is oxidised to .........

Which of the following statements is not correct?

When acidified $K_{2}C{r}_2{O}_7$ the solution is added to Sn⁺⁺ salt then Sn⁺⁺ changes to