Which one of the following conformation of cyclohexane is chiral?

Presence of a nitro group in a benzene ring

The pK_a of a weak acid (HA) is 4.5. The pOH of an aqueous buffered solution of HA in which 50% of the acid is ionized is :

In a sautrated solution of the sparingly soluble strong electrolyte AgIO₃ (Molecular mass = 283) the equilibrium which sets in is
AgIO_3(s) $$\leftrightharpoons$$ Ag⁺(aq) + $$IO_3^-$$
If the solubility product constant K_sp of AgIO₃ at a given temperature is 1.0 $$\times$$10⁻⁸, what is the mass of AgIO₃ contained in 100 ml of its saturated solution?