Q. Dissolving metallic $Zn$ in excess of $NaOH$ produces :-

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$Na_{2}ZnO_{2}$

$Zn\left(\right.OH\left(\left.\right)_{2}$

$ZnO$

$Zn\left(\right.OH\left(\left.\right)_{2}\&\left(Na\right)_{2}\left(ZnO\right)_{2}$

Solution:

$NaOH+Zn \rightarrow Na_{2}ZnO_{2}+H_{2}$

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2. If $8\,g$ of a non-electrolyte solute is dissolved in $114\, g$ of n-octane to reduce its vapour pressure to $80\%$, the molar mass (in $g \,mol^{-1})$ of the solute is [Given that molar mass of n-octane is $114 \,g\, mol^{-1}]$

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3. At standard conditions, if the change in the enthalpy for the following reaction is $-109 \,kJ\, mol^{-1}$ $H_{2(g)}+Br_{2(g)} \to 2HBr_{(g)}$ Given that bond energy of $H_{2}$ and $Br_{2}$ is $435\,KJ\,mol^{-1}$ and $192\,KJ\,mol^{-1}$ , respectively, what is the bond energy (in $KJ \,mol^{-1})$ of $HBr$ ?

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4. An organic compound contains $78 \%$ (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is: [Atomic wt. of $C$ is $12, H$ is $1$]

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5. The density of 2 M aqueous solution of NaOH is 1.28 g/cm$^3$. The molality of the solution is
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6. Given below are half cell reactions:
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$ E _{ Mn ^{2+} / MnO _{4}^{-}}^{\circ}=-1.510\, V$
$\frac{1}{2} O _{2}+2 H ^{+}+2 e ^{-} \rightarrow H _{2} O ,$
$ E _{ O _{2} / H _{2} O }^{\circ}=+1.223 \,V$
Will the permanganate ion, $MnO _{4}^{-}$liberate $O _{2}$ from water in the presence of an acid ?

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7. In water saturated air the mole fraction of water vapour is $0.02$. If the total pressure of the saturated air is $1.2\, atm$, the partial pressure of dry air is :

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8. Following limiting molar conductivities are given as
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$\lambda^{o}_{m}\left(K_{2}SO_{4}\right) = y S\,cm^{2} mol^{-1}$
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$\lambda^{o}_{m}\left(in \,S \,cm^{2} mol^{-1}\right)$ for $CH_3COOH$ will be-

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10. In the following reaction,
$H_3C-C\equiv CH\xrightarrow [{873\, K}] {\text{red hot iron tube}}$A,
the number of sigma(s) bonds present in the product A is :-

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