CBSE - Metals and Non-metals

1 Metals and Non-metals 

Silver jewellery turns blacks when exposed to air for long duration. This is due to the formation of : 

(1) Ag₂O 
(2) Ag₂S 
(3) Ag₂O + Ag₃N 
(4) AgN₃

2 Metals and Non-metals 

An element which shows allotrophy when burnt in air gives a gas with characteristic smell. The gas turns blue litmus red and is used as an insecticide. The element is

(1) C
(2) N
(3) P
(4) S

3 Metals and Non-metals 

The metal which does not react with cold as well as hot water but reacts with steam is

(1) Cu 
(2) Zn 
(3) Na 
(4) Fe

4 Metals and Non-metals 

The molecular formula of potash alum is 

(1) K₂SO₄.Al₂(SO₄)₃.24H₂O
(2) Ca(OCl)Cl
(3) )K₂SO₄
(4) Al₂(SO₄)₃.24H₂O

5 Metals and Non-metals 

The impurity present in the ore is called ..........

(1) gangue
(2) flux
(3) slag
(4) mineral

6 Metals and Non-metals 

Which of the following compounds is bad conductor of electricity?

(1) Ionic compound
(2) Electrovalent compound  
(3) Covalent compound
(4) None of these

7 Metals and Non-metals 

Bauxite is an ore of aluminium. It is concentrated suitably on treating with

(1) Conc. NaOH solution
(2) Na₂CO₃
(3) Coke and N₂
(4) Any of the above

8 Metals and Non-metals 

A metal is strongly heated in presence of air to form a black mass. So the metal is

(1) Potassium
(2) Platinum
(3) Copper
(4) Zinc

9 Metals and Non-metals 

Pick up the incorrect pair of metal-ore from the following

(1) Ag – Galena
(2) Mg – Carnallite
(3) Sn – Cassiterite
(4) Hg – Cinnabar

10 Metals and Non-metals 

Which of the following gas is known as tear gas ?

(1) methyl isocyanide
(2) sulphur dioxide
(3) chloropicrin
(4) nitrous oxide