Identify the product 'B' in the following reaction.

Toluene $\xrightarrow[\mathrm{CS}_2]{\text { Chromylchloride }} \mathrm{A} \xrightarrow{\mathrm{H}_3 \mathrm{O}^{+}} \mathrm{B}$

Which from following properties of lanthanoids is NOT true?

Which from the following defines enthalpy of a system?

Which from following salts is NOT derived from weak acid and weak base?