MCQ
If heat of neutralization is $-13.7\, KCal$ at $25\,^oC$ and $\Delta H_f^o (H_2O) = -68\, KCal$ then standard enthalpy of formation of $OH^-$ will be.....$KCal$
- A$54.3$
- ✓$-54.3$
- C$71.3$
- D$-71.3$
$\Delta \mathrm{H}_{\mathrm{r}}^{o}=\Delta \mathrm{H}_{\mathrm{f}}^{o}\left(\mathrm{H}_{2} \mathrm{O}\right)-\Delta \mathrm{H}_{\mathrm{f}}^{o}\left(\mathrm{OH}^{-}\right)$
$-13.7=-68-\Delta H_{f}\left(OH^{-}\right)$
$\Delta \mathrm{H}_{\mathrm{f}}\left(\mathrm{OH}^{-}\right)=-54.3 \,\mathrm{KCal}$
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$(A)\, F^-, Na^+, Mg^{+2}$ $(B) \,Ni, Cu, Zn$
$(C)\, N^{-3}, Cs^+, H^-$ $(D)\, Li, He, Be^{+2}$
$(a)$ $R_2SiO$ is repeating unit of linear silicones
$(b)$ $RSiCl_3$ on hydrolysis followed by dehydration gives linear silicones
$(c)$ Silicones can be used as heat insulator
$(d)$ Silica is soluble in $HF$
The correct statement$(s)$ is/are