Question

The total score for the correct statement(s) from the following is:
Given : $E_{L{i}^{\oplus }|Li}^{\ominus }=-3.05V$
$E_{N{a}^{\oplus }|Na}^{\ominus }=-2.71V$
$E_{K^{\oplus }|K}^{\ominus }=-2.93V$
Alkali metals react with water according to the following reaction (M = Alkali metals) :
$2M+H_{2}O\to 2MOH+H_2$
It is found that Li reacts gently with water, whereas K reacts violenly with water.

	Statements	Score
a.	$\Delta G$ values have nothing to do with kinetics of the reaction.	4
b.	The metal having large standard oxidation potential will have lesseer reactivity.	3
c.	Potassium (K) has low melting point and heat of reaction which is sufficient to make it melt or even vapourize. This leads to expotential increase in its surface area.	2
d.	The ionization potential of K is smaller than that of Li.	1

Answer 1

(6)
statements (a) and (c) are correct
So total score = 4 + 2 =6
Statement (a) : $\Delta G$ is a thermodynamic property so it is not related to rate of the reaction, i.e., kinetics of the reactions. S, (a) is correct.
statement 9b) : large $E_{oxidation}^{\ominus }$ means more tendency of metal to undergo oxidation $(M\to M^{\oplus }+e^{-}$, so more reactive metal. so, statement (b) is wrong.
Statement (c): Factual statement and is correct.
Statement (d) : $E_{oxideLi|L{i}^{\oplus }}^{\ominus }>E_{oxidK|K^{\oplus }}^{\ominus }$
It means higher the oxidation potential moere easily the metal is oxidized, i.e.,
$I{E}_1$ of Li is smaller than K.
Although Li is smaller in size than K, so its $I{E}_1$ should be more. But due to high -ve hydration energy of $L{i}^{\oplus }$, it compensates the high $I{E}_1$ of Li.
$\begin{array}{cccccccccccc}Li\left(s\right)& \stackrel{\Delta H-Sub}{\to }& li\left(g\right)& \stackrel{I{E}_1}{}& L{i}^{\oplus }& +& e^{-}aq& \downarrow & \Delta H_{H}ydradion& L{i}^{\oplus }\left(aq\right)& & \\ E_{oxid}^{\ominus }=& \Delta H_{sub}^{\ominus }& +& I{E}_1+& \Delta H_{Hydration}^{\ominus }& & & & & & & \end{array}$
So, IP (ionization potential) is determined by all the three factors, i.e., sublimation, $I{E}_1$ and hydration energy. So, statement (d) is wrong.