41.

The best method for the preparation of 2, 2-dimethylbutane is via the reaction of

• Me₃CBr and MeCH₂Br in Na/ether

• (Me₃C)₂CuLi and MeCH₂Br

• (MeCH₂)₂CuLi and Me₃CBr

• Me₃CMgI and MeCH₂I

Acid catalysed hydrolysis of ethyl acetate follows a pseudo-first order kinetics with respect to ester. If the reaction is carried out with large excess of ester, the order with respect to ester will be

• 1.5

• 0

• 0.5

• 1

The half-life for decay of ¹⁴C by β-emission is 5730 yr. The fraction of ¹⁴C decays, in a sample that is 22920 yr old, would be

• $\frac{1}{8}$

• $\frac{1}{16}$

• $\frac{7}{8}$

• $\frac{15}{16}$

The measured freezing point depression for a 0.1 m aqueous CH₃COOH solution is 0.19°C. The acid dissociation constant K_a at this concentration will be (Given, K_f the molal cryoscopic constant = 1.86 K kg mol^-1)

• 4.76 × 10^-5

• 4 × 10^-5

• 8 × 10^-5

• 2 × 10^-5

The ore chromite is

• FeCr₂O₄

• CoCr₂O₃

• CrFe₂O₄

• FeCr₂O₃

'Sulphan' is

• a mixture of SO₃ and H₂SO₅

• 100% conc. H₂SO₄

• a mixture of gypsum and conc. H₂SO₄

• 100% oleum (a mixture of 100% SO₃ in 100% H₂SO₄)

Amongst [Ni(H₂O)₆]²⁺; [Ni(PPh₃)₂Cl₂]; [Ni(CO)₄] and [Ni(CN₄)]^2- the paramagnetic species are

• [NiCl₄]^2-; [Ni(H₂O)₆]²⁺; [Ni(PPh₃)₂Cl₂]

• [Ni(CO)₄]; [Ni(PPh₃)₂Cl₂]; [NiCl₄]^2-

• [Ni(CN₄)]^2- ; [Ni(H₂O)₆]²⁺ ; [NiCl₄]^2-

• [Ni(PPh₃)₂Cl₂] ; [Ni(CO)₄]; [Ni(CN₄)]^2-

The important advantage(s) of Lintz and Donawitz (L.D.) process for the manufacture of steel is (are)

• the process is very quick

• operating costs are low

• better quality steel is obtained

• scrap iron can be used

Consider the following reaction for 2NO₂(g) + F₂(g) → 2NO₂Fg). The expression for the rate of reaction in terms of the rate of change of partial pressure of reactant and product is/are

• rate = $-\frac{1}{2}\left[\frac{\mathrm{dp}\left({\mathrm{NO}}_2\right)}{\mathrm{dt}}\right]$

• rate = $\frac{1}{2}\left[\frac{\mathrm{dp}\left({\mathrm{NO}}_2\right)}{\mathrm{dt}}\right]$

• rate = $-\frac{1}{2}\left[\frac{\mathrm{dp}\left({\mathrm{NO}}_2\mathrm{F}\right)}{\mathrm{dt}}\right]$

• rate = $\frac{1}{2}\left[\frac{\mathrm{dp}\left({\mathrm{NO}}_2\mathrm{F}\right)}{\mathrm{dt}}\right]$

A conductivity cell has been calibrated with a 0.01 M 1 : 1 electrolyte solution (specific conductance, k = 1.25 × 10^-3S cm^-1) in the cell and the measured resistance was 800 $\Omega$ at 25°C. The cell constant will be

• 1.02 cm^-1

• 0.102 cm^-1

• 1.00 cm^-1

• 0.5 cm^-1