
- A

- ✓

- C

- D








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$A$. has been used in spaceship
$B$. has as efficiency of $40 \%$ to produce electricity
$C$. uses aluminium as catalysts
$D$. is eco-friendly
$E$. is actually a type of Galvanic cell only
$1$. propanal
$2$. trichloroethanal
$3$. methanal
$4$. ethanal
$5$. benzaldehyde
${B^{3 + }}_{(aq.)} + 3{e^ - } \to B(s)$ ; $E = 0.6\ Volt$
Using above information find the ion which will be deposited first at cathode if solution containing $A_{(aq.)}^{2 + }$ & $B_{(aq.)}^{ 3+ }$ is electrolysed
| List $I$ | List $II$ |
| $P.$ $PbO _2+ H _2 SO _4 \xrightarrow{?} PbSO _4+ O _2+$ other product | $1.$ NO |
| $Q.$ $Na _2 S _2 O _3+ H _2 O \xrightarrow{?} NaHSO _4+$ other product | $2.$ $I_2$ |
| $R.$ $N _2 H _4 \xrightarrow{\text { ? }} N _2+$ other product | $3.$ Warm |
| $S.$ $XeF _2 \xrightarrow{?} Xe +$ other product | $4.$ $Cl _2$ |
Codes: $ \quad P \quad Q \quad R \quad S $
(Atomic numbers $Ce =58, Gd =64$ and $Eu =63 .)$
$(a)$ $\left( NH _{4}\right)_{2}\left[ Ce \left( NO _{3}\right)_{6}\right]$
$(b)$ $Gd \left( NO _{3}\right)_{3}$ and
$(c)$ $Eu \left( NO _{3}\right)_{3}$
Answer is :