The pH of an aqueous solution of CH₃COONa of concentration C(M) is given by

• 7 - $\frac{1}{2}$pK_a - $\frac{1}{2}$log C

• $\frac{1}{2}$pK_w + $\frac{1}{2}$pK_b + $\frac{1}{2}$log C

• $\frac{1}{2}$pK_w - $\frac{1}{2}$pK_b - $\frac{1}{2}$log C

• $\frac{1}{2}$pK_w + $\frac{1}{2}$pK_a + $\frac{1}{2}$log C

If the equilibrium constants of the following equilibria,

SO₂ + $\frac{1}{2}$O₂ → SO₃ and 2SO₃ → 2SO₂ + O₂

are given by K₁ and K₂ respectively, which of the following realation is correct?

• K₂ = ${\left(\frac{1}{{\mathrm{K}}_1}\right)}^2$

• K₁ = ${\left(\frac{1}{{\mathrm{K}}_2}\right)}^3$

• K₂ = $\left(\frac{1}{{\mathrm{K}}_1}\right)$

• K₂ = (K₁)²

The energy of an electron in first Bohr orbit of H-atom is -13.6 eV. The possible energy value of electron in the excited state of Li²⁺ is

• -122.4 eV

• 30.6 eV

• -30.6 eV

• 13.6 eV

The amount of the heat released when 20 mL 0.5 M NaOH is mixed with 100 mL 0.1 M HCl is × kJ. The heat of neutralisation is

• -100 x kJ/mol

• -50 x kJ/mol

• + 100 x kJ/mol

• +50 x kJ/mol

5.

Which one of the following has the lowest ionisation energy?

• 1s², 2s², 2p⁶

• 1s², 2s², 2p⁶, 3s¹

• 1s², 2s², 2p⁵

• 1s², 2s², 2p³

2 g of metal carbonate is neutralised completely by 100 mL of 0.1 N HCl. The equivalent weight of metal carbonate is

• 50

• 100

• 150

• 200

The representation of the ground state electronic configuration of He by box-diagram as  is wrong because it violates

• Heisenberg's uncertainty principle

• Bohr's quantization theory of angular momenta

• Pauli exclusion principle

• Hund's rule

The electronic transitions from n = 2 to n= 1 will produce shortest wavelength in (where n = principal quantum state)

• Li²⁺ 

• He⁺

• H

• H⁺

In the following electron-dot structure, calculate the formal charge from left to right nitrogen atom; 

• -1, -1, +1

• -1, +1, -1

• +1, -1, -1

• +1, -1, +1

If the molecular wt. of Na₂SO₃ and I₂ are M₁ and M₂ respectively then what will be the equivalent weight of Na₂SO₃ and I₂ in the following reaction?

2S₂O${}_3^{2-}$ + I₂ → S₄O${}_6^{2-}$ + 2I^-

• M₁, M₂

• M₁, M₂ /2

• 2M₁, M₂

• M₁, 2M₂