CBSE Class 8 - Science - CH4 Metals and Non-Metals (NCERT Exemplar Answers) (#cbseNotes)

Metals and Non-Metals 

NCERT Exemplar Answers

Multiple Choice Questions

Q1: Which of the following is not a metal?

(a) copper
(b) sulphur
(c) aluminium
(d) iron


Q2: The substance that will be flattened on beating with a hammer is

(a) crystal of iodine
(b) lump of sulphur
(c) piece of coal
(d) zinc granule




Q3: Boojho has learnt that non-metals on beating with a hammer are generally broken into pieces. Which of the following is a non-metal?

(a) iron nail
(b) aluminium wire
(c) copper plate
(d) piece of coal


Q4: Materials which can be drawn into wires are called ductile. Which of the following is not a ductile material?

(a) silver
(b) copper
(c) sulphur
(d) aluminium


Q5: Metals are generally hard. Which of the following metals is an exception and can be cut with a knife?

(a) iron
(c) gold
(b) sodium
(d) magnesium


Q6: Metals are generally solid. Which of the following metals is in the liquid state at room temperature?

(a) mercury
(b) silver
(c) aluminium
(d) sodium


Q7: Metals generally react with dilute acids to produce hydrogen gas. Which one of the following metals does not react with dilute hydrochloric acid?

(a) magnesium
(b) aluminium
(c) iron
(d) copper


Q8. Which of the following reacts with cold water vigorously?

(a) carbon
(b) sodium
(c) magnesium
(d) sulphur


Q9: The metal which produces hydrogen gas on reaction with dilute hydrochloric acid as well as sodium hydroxide solution is

(a) copper
(b) iron
(c) aluminium
(d) sodium


Q10: Which of the following non-metals reacts and catches fire on exposure to air?

(a) phosphorus
(b) nitrogen
(c) sulphur
(d) hydrogen


Q11: Generally metallic oxides are basic and non-metallic oxides are acidic in nature. Solution of which of the following oxides in water will change the colour of blue litmus to red?

(a) sulphur dioxide
(b) magnesium oxide
(c) iron oxide
(d) copper oxide



Q12: Which of the following property is not responsible for copper to be used as electrical conduction wires?

(a) ductility
(b) colour
(c) good conductor of electricity
(d) it is solid




Answer:

1: (b) sulphur (Rest are metals)

2: (d) zinc granule (Metals are malleable in general.)

3: (d) piece of coal (In general, Non-metals are brittle in nature.)

4: (c) sulphur (Sulphur is a non-metal.)

5: (b) sodium (Sodium, Potassium are soft and can be cut by knife.)

6: (a) mercury (Mercury (Symbol: Hg), is also called liquid metal.)

7: (d) copper (In reactivity series, Copper is less reactive than Hydrogen. Cu can't displace hydrogen in HCl (Hydrochloric acid))

8: (b) sodium (Sodium reacts with water violently, so it is kept under kerosene)

9: (c) aluminium (Al is an amphoteric metal which reacts with both acids and bases. )

10: (a) phosphorus ( Phosphorus has low ignition temperature i.e. 35°C. At room temperature, it reches its ignition point easily and catches fire. )


11: (a) sulphur dioxide (Non metal oxides are acidic. SO₂ when mixed with water forms sulphurous acid.)

12: (b) colour