Question

Observe the given diagram and fill in the blanks by choosing the correct option.

	$X$	$Y$	$Z$
(a)$\,\,$	$H_{2(g)}$ at $1 \,atm$$\,\,$	$10^{-2}M\,H^+$$\,$	Finely divided $Pt$$\,\,$
(b)$\,\,$	$H_{2(g)}$ at $1 \,bar$$\,\,$	$1.00\,M\,H^+$$\,\,$	Finely divided $Pt$$\,\,$
(c)$\,\,$	$1.00\,M\,H^+$$\,\,$	$H_{2(g)}$ at $1 \,bar$$\,\,$	Finely divided $Ni$$\,\,$
(d)$\,\,$	$H_{2(g)}$ at $1 \,bar$	$1.00\,M\,H^+$$\,\,$	$Pt$ granules

• A. a
• B. b
• C. c
• D. d

Answer 1

Answer: (B)

This is standard hydrogen electrode.
It contain platinum wire,
From $x , H _{2}( g )$ is passed at $1 bar$.
where as, $y$ is $1\, M$ concentration of $H ^{+}$(acid)
$Z$ is finely divided platinum coated platinum on platinum foil.
Overall reaction- $H ^{+}( aq )+2 e ^{-} \longrightarrow H _{2}( g )$