81.

A solution of 4.5 g of a pure non-electrolyte in 100 g of water was found to freeze at 0.465°C. The molecular weight of the solute is closest to (k_f =1.86)

• 180.0

• 135.0

• 172.0

• 90.0

Irrespective of the source, pure sample of water always yields 88.89% mass of oxygen and 11.11 % mass of hydrogen. This is explained by the law of; 

• conservation of mass

• constant composition

• multiple proportion

• Gay-Lussa

32g of O₂, 2g of H₂ and 28g of N₂ at STP, occupy separately a volume of:

• 1L

• 2L

• 22.4L

• 2.24L

Identify the incorrect statement :

• The molarity of a solution is independent of temperature

• The tendency for catenation is much higher for carbon than for silicon

• Nitriles and iso nitriles constitute metamers

• t-butyl 1-carbocation has planar carbons and is very reactive

The pH of 0.005 M H₂SO₄ is :

• 2.5

• 1.5

• 1.0

• 2.0

A 5 molar solution of H₂SO₄ is diluted from 1 L to 10 L. What is the normality of the solution ?

• 0.25 N

• 1 N

• 2 N

• 7 N

The pH of the solution 5 mL of M/5 HCl + 10 mL of M/10 NaOH is

• 5

• 3

• 7

• 8

If the heat of formation of CO2 is -393 kJ. The amount of heat evolved in the formation of 0.176 kg of CO₂ is

• -1357.9kJ

• -1275.9kJ

• -1572.0kJ

• -1165.5kJ

In a nuclide, one a.m.u. of mass is dissipated into energy to bind its nucleons. The energy equivalent of this mass is

• 931.5 eV

• 931.5 × 10⁶ eV

• 931.5 × 10⁶ MeV

• 931.5 MV

What is the volume (in litres) of oxygen at STP required for complete combustion of 32 g of CH₄?

(Molecular weight of CH₄ is 16)

• 44.8

• 89.6

• 22.4

• 179.2