Class 12 cbse ( chemistry)

How many unit cells are divided equally in a face centred cubic lattice?

• 2

• 4

• 6

• 8

Copper crystalline in FCC with a unit cell length of 361 pm. what is the radius of a copper atom?

• 128 pm

• 157 pm

• 181 pm

• 108 pm

The number of moles of Nacl in 3 litres of 3M solution is

• 1

• 3

• 9

• 27

At 100°C the vapour pressure of a solution of 6.5g of solute in 100g of water is 732mm. If Kb is 0.52 K/m the boiling point of the solution is

• 102°C

• 103°C

• 101°C

• 100°C

What is mole fraction of solute in 1.00m aqueous solution?

• 0.0354

• 0.0177

• 0.177

• 1.770

The weight of silver displaced by a quantity of electricity which displaces 5600ml of O2 at STP will be

• 5.4g

• 10.8g

• 54.9g

• 108.0g

On electrolysis of dilute sulphuric acid using platinum electrodes the product obtained at the anode will be

• Hydrogen

• Oxygen

• Hydrogen sulphide

• Sulphur dioxide

The avg. rate and instantaneous rate of a reaction are equal

• At the start

• At the end

• In the middle

• When two rates have a time interval equal to zero

A catalyst alters which of the following in a chemical reaction?

• Entropy

• Enthalpy

• Internal energy

• Activation energy

If the dispersed phase is a liquid and dispersion medium is solid the colloid is known as

• Foam

• Sol

• Emulsion

• Gel