Choose the statements which are incorrect in the case of Lanthanoids.
A. $\mathrm{Ce}^{4+}$ is diamagnetic while $\mathrm{Sm}^{3+}$ is paramagnetic.
B. The atomic size of the transition metals having atomic number greater than 71 are very close to that of the elements above them.
C. Lanthanoids react with hot water forming water soluble $\mathrm{Ln}(\mathrm{OH})_3$ with the liberation of $\mathrm{O}_2$.
D. The general electronic configuration of Lanthanoids is $(n-2) \mathrm{f}^{1-14} 5 \mathrm{~d}^0 6 \mathrm{~s}^2$, where $n=6$.
Given below are 2 statements: one Assertion and the other Reason. Which one of the following options is correct?
Assertion : Sulphur dioxide and Hydrogen peroxide can act as both oxidising and reducing agents but Nitric acid can act as only oxidising agent.
Reason : Sulphur and Oxygen can exhibit more than one stable oxidation states while Nitrogen does not.