Assertion (A) Separation of Zr and Hf is difficult.
Reason (R) Zr and Hf lie in the same group of the periodic table.
Assertion (A) Toxic metal ions are removed by the chelating ligands.
Reason (R) Chelate complexes tend to be more stable.
Assertion (A) IUPAC name of the compound
Reason (R) In IUPAC nomenclature, ether is regarded as hydrocarbon derivative in which a hydrogen atom is replaced by-OR or- $$\mathrm{O} A r$$ group [where, $$R=$$ alkyl group and $$A r=\operatorname{aryl}$$ group].
Assertion (A) The reaction
$$\begin{aligned} 2 \mathrm{NO}+\mathrm{O}_2 & \longrightarrow 2 \mathrm{NO}_2 \\ \text { and } \quad 2 \mathrm{CO}+\mathrm{O}_2 & \longrightarrow 2 \mathrm{CO}_2 \end{aligned}$$
proceeds at the same rate because they are similar.
Reason (R) Both the reactions have same activation energy.