Solubility product of silver bromide is 5.0 $$\times$$ 10^–13. The quantity of potassium bromide (molar mass taken as 120g of mol^–1) to be added to 1 litre of 0.05 M solution of silver nitrate to start the precipitation of AgBr is

Solid Ba(NO₃)₂ is gradually dissolved in a 1.0 $$\times$$ 10^-4 M Na₂CO₃ solution. At what concentration of Ba²⁺ will a precipitate begin to form ?
(K_sp for BaCO₃ = 5.1 $$\times$$ 10⁻⁹ )

The equilibrium constants K_P1 and K_P2 for the reactions X $$\leftrightharpoons$$ 2Y and Z $$\leftrightharpoons$$ P + Q, respectively are in the ratio of 1 : 9. If the degree of dissociation of X and Z be equal then the ratio of total pressure at these equilibria is

Four species are listed below
i. $$HCO_3^−$$
ii. $$H_3O^+$$
iii. $$HSO_4^−$$
iv. $$HSO_3F$$
Which one of the following is the correct sequence of their acid strength?