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

• 7 - 1/2 pK_a - 1/2 log C

• 1/2 pK_w + 1/2 pK_b + 1/2 log C

• 1/2 pK_w - 1/2 pK_b - 1/2 log C

• 1/2 pK_w - pK_a + 1/2 log C

2.

If the equilibrium constants of the following equilibria,

SO₂ + 1/2O₂ $\to$ SO₃ and 2SO₃ $\to$ 2SO₂ + O₂

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

• K₂ = (1/K₁)²

• K₁ = (1/K₃)³

• K₂ = (1/K₁)

• 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 x kJ. The heat of neutralisation is:

• - 100 x kJ/mol

• - 50 x kJ/mol

• + 100 x kJ/mol

• + 50 x kJ/mol

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 HCI. The equivalent weight of metal carbonate is:

• 50

• 100

• 150

• 200

An electric current is passed through an aqueous solution of a mixture of alanine (isoelectric point 6.0), glutamic acid (3.2) and arginine (10.7) buffered at pH 6. What is the fate of the three acids?

• Glutamic acid migrates to anode at pH 6. Arginine is present as a cation and migrates to the cathode. Alanine in a dipolar ion remains uniformly distributed in solution

• Glutamic acid migrates to cathode and others remain uniformly distributed in solution

• All three remain uniformly distributed in solution

• All three move to cathode

The representation of the ground state electronic configuration of He by box-diagram as 

$\uparrow \uparrow$

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; $\stackrel{\mathbf{.}\mathbf{.}}{\underset{\mathbf{.}\mathbf{.}}{\mathrm{N}}}=\mathrm{N}=\stackrel{\mathbf{.}\mathbf{.}}{\underset{\mathbf{.}\mathbf{.}}{\mathrm{N}}}$ :

• -1 , -1 , +1

• -1 , +1 , -1

• +1 , -1 , -1

• +1 , -1 , +1