2-hydroxypropanoic acid has a central carbon atom, which is linked to four different groups. This carbon atom is called chiral carbon atom and the molecule is called a chiral molecule. Hence, 2-hydroxy propanoic acid shows optical isomerism.

Enantiomers

The sp³d² and d²sp³ hybridisation of central atom leads to octahedral geometry.

$\stackrel{1}{{\mathrm{CH}}_3}-\stackrel{2}{\underset{\stackrel{\uparrow }{{\mathrm{sp}}^2}}{\mathrm{CH}}}=\stackrel{3}{\underset{\stackrel{\uparrow }{\mathrm{sp}}}{\mathrm{C}}}=\stackrel{4}{\mathrm{CH}}-\stackrel{5}{{\mathrm{CH}}_3}$

Ca₃(PO₄)₂(s) $\rightleftharpoons$$\frac{3{\mathrm{Ca}}^{2+}}{3\mathrm{y}}$ (q) + 2PO₄^3- (aq)

so, K_SP = [Ca²⁺]³ . [PO₄^3-]²

= (3y)^3.(2y²)

= 27y³ x 4y²

= 108y⁵

The ease of nitration of the hydrocarbons depends upon the stability of arenium ion formed.

In compound II, the carbonium ion has two methyl groups (with +I effect) capable of partially neutralising the positive charges on the ring carbon atoms. In compound I and II, only one methyl group can act in this way. Moreover, in compound III two methyl groups have +I effet, whereas in compound I only one methyl group with +I effect is present. Thus, the stability of arelium ion and ease of nitration follows the order,

II > III > I

Volume strength = 5.6 x normality

or normality = $\frac{\mathrm{volume} \mathrm{strength}}{5.6}$ = $\frac{30}{5.6}$ = 5.35 N

$\therefore$ Equivalent mass of S₂O₃^2- = $\frac{{\mathrm{M}}_1}{1}$ = M₁  and equivalent mass of I₂ = $\frac{{\mathrm{M}}_2}{2}$

The formation of ozone in the stratosphere takes place by the interaction of O₂ molecules with high energetic ultraviolet radiation.

O₂ $\to$ O + O

O + O₂ $\to$ O₃

An $\mathrm{\alpha }$-emission reduces the atomic mass by 4 and atomic number by 2, whereas a $\mathrm{\beta }$-emission increases the atomic number by 1 with no change in atomic mass.

${\mathrm{M}}_{\mathrm{Y}}^{\mathrm{X}}$ $\stackrel{-\mathrm{\alpha }}{\to }$ ${\mathrm{N}}_{\mathrm{Y}-2}^{\mathrm{X}-4}$ $\stackrel{-\mathrm{\alpha }}{\to }$ ${\mathrm{O}}_{\mathrm{Y}-4}^{\mathrm{X}-8}$ $\stackrel{-\mathrm{\beta }}{\to }$ ${\mathrm{P}}_{\mathrm{Y}-3}^{\mathrm{X}-8}$

Number of neutrons = mass number - atomic number

= X - 8 - Y + 3

= X - Y - 5

Iso-butylene directly adds a molecule of water in the presence of H₂SO₄ as a catalyst to form tertiary butyl alcohol.