pBlock ElementsII - Result Question 104
####101. Explain the following in one or two sentences.
(i) Magnesium oxide is used for the lining of steel making furnace.
(ii) The mixture of hydrazine and hydrogen peroxide with a copper (II) catalyst is used as a rocket fuel.
(iii) Orthophosphorous acid is not tribasic acid.
(iv) The molecule of magnesium chloride is linear, whereas that of stannous chloride is angular.
$(1987,4 M)$
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Solution:
- (i) $MgO$ is used for the lining of steel making furnace because it forms slag with impurities, and thus helps in removing them from iron.
(ii) The mixture of $N _2 H _4$ and $H _2 O _2$ (in presence of $Cu$ (II) catalyst) is used as a rocket propellant because the reaction is highly exothermic and large volumes of gases is evolved.
$$ N _2 H _4(l)+2 H _2 O _2(l) \longrightarrow N _2(g)+4 H _2 O(g) $$
(iii) In orthophosphorus acid $\left(H _3 PO _3\right)$ only two of the three $H$ are replaceable as
(Only $H$ of $-OH$ are acidic)
(iv) In $MgCl _2, Mg$ is $s p$-hybridised while in $SnCl _2, Sn$ is $s p^{2}$-hybridised with a lone pair at $Sn$. Hence, $MgCl _2$ is linear while $SnCl _2$ is angular.
