The electronic configuration of ₅₉Pr ( praseodimium) is

• [₅₄Xe] 4f²5d¹6s²

• [₅₄Xe] 4f¹5d¹6s²

• [₅₄Xe] 4f³6s²

• [₅₄Xe] 4f³5d²

The bond lenght (pm) of F₂, H₂, Cl₂ and I₂, respectively is:

• 144, 74, 199, 267

• 74, 144, 199, 267

• 74, 267, 199, 144

• 144, 74, 267, 199

How many emission spectral lines are possible when hydrogen atom is excited to nth energy level?

• $\frac{\mathrm{n}(\mathrm{n}+1)}{2}$

• $\frac{(\mathrm{n}+1)}{2}$

• $\frac{(\mathrm{n}-1)\mathrm{n}}{2}$

• $\frac{{\mathrm{n}}^2}{4}$

4.

Which of the following corresponds to the energy of the possible excited state of hydrogen?

• -13.6 eV

• 13.6 eV

• -3.4 eV

• 3.4 eV

Which one of the following statement is correct for d⁴ ions [ P = pairing energy]

• When Δ₀ > P, low-spin complex form

• When Δ₀ < P, low-spin complex form

• When Δ₀ > P, high-spin complex form

• When Δ₀ > P, both high and low-spin complex form

Commercially available H₂SO₄ is 98 g by H₂SO₄ and 2g by weight of water. It's density is 1.38 g cm^-3. Calculate the molality (m) of  H₂SO₄ (molar mass of  H₂SO₄  is 98 g mol^-1). 

• 500 m

• 20 molal

• 50 m

• 200 m

Standard enthalpy (heat) of formation of liquid water at 25°C is around

 H₂(g) + $\frac{1}{2}$O₂(g) → H₂O (l)

• -237 kJ/mol

• 237 kJ/mol

• - 286 kJ/mol

• 286 kJ/mol

The species having pyramidal shape according to VSEPR theory is

• SO₃

• BrF₃

• SiO${}_3^{2-}$

• OsF₂

Given ΔH_f° for CO₂(g) , CO(g) and H₂O(g) are -393.5, -110.5 and -241.8 kJ mol^-1, respectively. The ΔH_f° [in kJ mol^-1] for the reaction

CO₂(g) + H₂(g) → CO(g) + H₂O (g) is

• 524.1

• -262.5

• -417

• 412

Oxidation of cyclohexene in presence of acidic potassium permaganate leads to

• glutaric acid

• adipic acid

• pimelic acid

• succinic acid