All isotopes of the same element have .................

• different atomic numbers and different atomic mass

• different atomic numbers and the same atomic mass

• the same atomic number but different atomic masses

• the same atomic number but different atomic masses

Nitric acid does not react with

• Gold

• Copper

• Zinc

• Zinc

The material used in electric heater is

• Tungsten

• Nichrome

• Brass

• Brass

Which of the metals has the maximum thermal conductivity?

• Iron

• Aluminium

• Silver

• Silver

Silver gets corroded due to ................ in air.

• Oxygen

• Hydrogen Sulphide

• Carbon dioxide

• Carbon dioxide

Which of the following is a radioactive element?

• Cobalt

• Uranium

• Argon

• Argon

77.

The chemical name of quartz is.................

• Calcium oxide

• Calcium phosphate

• Sodium phosphate

• Sodium phosphate

...................gives hardness to stainless steel.

• Zinc

• Lead

• Carbon

• Carbon

Which of the following is not soluble in water?

• Lead sulphate

• Zinc sulphate

• Potassium sulphate

• Potassium sulphate

Activated Charcoal is used to remove colouring matter from pure substances by .............

• Bleaching

• Oxidation

• Adsorption

• Adsorption