Additin of sodium hydroxide solution to a weak acid (HA)results in a buffer of pH 6. If ionition constant of HA is 10^$$-$$5, the ratio of salt to acid concentration in the buffer solution will be :

5 g of Na₂SO₄ was dissolved in x g of H₂O. The change in freezing point was found to be 3.82^oC. If Na₂SO₄ is 81.5% ionised, the value of x

(K_f for water=1.86^oC kg mol⁻¹) is approximately :

(molar mass of S = 32 g mol⁻¹ and that of Na = 23 g mol⁻¹)

If the shortest wavelength in Lyman series of hydrogen atom is A, then the longestwavelength in Paschen series of He⁺ is :

For a reaction, A(g) $$ \to $$ A($$\ell $$); $$\Delta $$H= $$-$$ 3RT.
The correct statement for the reaction is :