Three friends, P, Q, and R, are solving a puzzle with statements:
(i) If P is a knight, Q is a knave.
(ii) If Q is a knight, R is a spy.
(iii) If R is a knight, P is a knave. Knights always tell the truth, knaves always lie, and spies sometimes tell the truth. If each friend is either a knight, knave, or spy, who is the knight?
Standard electrode potentials of Na, Ni, and Cl are given. Which one has the highest reducing power?
$\text{Cl}_{2}(g) + 2e^- \&\rightarrow 2\text{Cl}^- $
$\text{Ni}^{2+} + 2e^- \&\rightarrow \text{Ni}(s) $
$\text{Na}^+ + e^- \&\rightarrow \text{Na}(s) $