Question

The standard reduction electrode potentials of the three electrodes $P, Q $ and $R$ are respectively $ -1.76\,V,0.34\,V $ and $0.8 \,V$, then

• A. metal $Q$ will displace the cation of $P$ from its aqueous solution and deposit the metal $P$
• B. both metals $Q$ and $R$ will displace the cation of $P$ from its aqueous solution and deposit the metal $P$
• C. metal $R$ will displace the cation of $P$ from its aqueous solution and deposit the metal $P$
• D. metal $P$ will displace the cation of $R$ from its aqueous solution and deposit the metal $R$

Answer 1

Answer: (D)

The metal that has less standard reduction electrode potential or more negative reduction potential, can displace the other metals (cations) from their aqueous solution. Among the given, $P$ has most negative standard reduction potential, so it will displace $Q$ and $R$ cations from the aqueous solution and deposit them.