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Class 10 Science Chapter 3: Metals and Non-metals MCQs with answers

10 multiple-choice questions on Metals and Non-metals, each with its answer and the reason, written from the NCERT chapter. Open a question's solution to check your working; then take the free test to find your next chapter.

Question 1
A sealed glass ampoule in a school store holds a dark red-brown liquid. The label says the element is a non-metal. The element is
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Answer: (c) bromine

Non-metals are solids or gases, the one exception being bromine, which is a liquid. Mercury is a liquid but a metal; iodine and sulphur are solids.

Question 2
At a cable factory in Renukoot, copper rods are pulled through smaller and smaller holes until they become fine wires. The property of copper that makes this possible is
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Answer: (a) ductility

Drawing a metal into thin wires uses ductility. Malleability is beating into sheets; sonorousness and lustre are sound and shine.

Question 3
Temple bells and school bells are cast from metals and not from wood or plastic, chiefly because metals
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Answer: (b) are sonorous

A bell must ring when struck. Metals that produce a sound on striking a hard surface are sonorous.

Question 4
A laboratory assistant places a small silvery piece of metal X on her palm and it slowly turns into a liquid. X is most likely
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Answer: (b) gallium

Gallium has so low a melting point that it melts on the palm. Mercury is already a liquid at room temperature, so it could not turn into one; sodium and iron stay solid at body temperature.

Question 5
A student sorting elements finds a solid that shines like a metal, yet it is classed as a non-metal. The element is
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Answer: (c) iodine

Iodine is a non-metal but it is lustrous. Sulphur is a dull solid, bromine a liquid and oxygen a gas.

Question 6
Which statement about the allotropes of carbon is correct?
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Answer: (c) Diamond is the hardest natural substance and graphite conducts electricity.

Diamond is the hardest natural substance known, with a very high melting and boiling point; graphite conducts electricity. The other options swap or deny these facts.

Question 7
An electrician holds the bare end of a copper wire in a gas flame for a minute. The end does not burn but turns black. The black coating is
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Answer: (a) copper(II) oxide, CuO

Copper does not burn, but on heating in air it combines with oxygen and is coated with black copper(II) oxide: 2Cu + O₂ → 2CuO.

Question 8
An oxide Y dissolves in dilute hydrochloric acid and also in sodium hydroxide solution, and in each case a salt and water are formed. Y could be
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Answer: (b) ZnO

An oxide that reacts with both acids and bases to give salt and water is amphoteric; zinc oxide is one. MgO and Na₂O are basic and react only with acids; CO₂ is acidic.

Question 9
Sodium oxide is added to water. The equation for the change is
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Answer: (a) Na₂O + H₂O → 2NaOH

Most metal oxides are insoluble, but sodium oxide dissolves to form the alkali sodium hydroxide: Na₂O + H₂O → 2NaOH. No hydrogen is formed, and option c is not balanced.

Question 10
A factory in Hosur thickens the oxide coat on aluminium window frames by anodising. In this process the frame is made the
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Answer: (d) anode, in dilute sulphuric acid

In anodising the aluminium article is made the anode and electrolysed with dilute sulphuric acid; the oxygen evolved at it thickens the oxide layer.

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