Consider the following-reactions (i) LiOH + CO\(_2\) \(\rightarrow\) Li\(_2\)CO\(_3\) + H\(_2\)O (ii) 2H\(_2\) + O\(_2\)

Explanation

In order to determine which of the given reactions are redox reactions, we need to identify if there is a transfer of electrons between species in each reaction, meaning that one species is reduced (gains electrons) while another is oxidized (loses electrons).

Let's analyze each reaction:

(i) LiOH + CO\(_2\) \(\rightarrow\) Li\(_2\)CO\(_3\) + H\(_2\)O: In this reaction, lithium (Li) in LiOH does not change its oxidation state, and neither does carbon (C) in CO\(_2\). Therefore, this reaction is not a redox reaction.

(ii) 2H\(_2\) + O\(_2\) \(\rightarrow\) 2H\(_2\)O: In this reaction, hydrogen (H) goes from an oxidation state of 0 in H\(_2\) to +1 in H\(_2\)O, while oxygen (O) goes from an oxidation state of 0 in O\(_2\) to -2 in H\(_2\)O. This means that hydrogen is oxidized, and oxygen is reduced, so this reaction is a redox reaction.

(iii) 2Cu + O\(_2\) \(\rightarrow\) 2CuO: In this reaction, copper (Cu) goes from an oxidation state of 0 in Cu to +2 in CuO, while oxygen goes from an oxidation state of 0 in O\(_2\) to -2 in CuO. This means that copper is oxidized, and oxygen is reduced, so this reaction is a redox reaction.

(iv) HCl + AgNO\(_3\) \(\rightarrow\) AgCl + HNO\(_3\): In this reaction, hydrogen (H) and chlorine (Cl) in HCl exchange places with silver (Ag) and nitrate (NO\(_3\) in AgNO\(_3\), but their oxidation states do not change. This is an example of a metathesis reaction, not a redox reaction.

Based on the analysis, the correct answer isOption D, as only reactions (ii) and (iii) are redox reactions.