NCERT Class X Science Class: Chapter –3. Metals and Nonmetals– Part-5

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Question 27:

Which among the following statements is incorrect for magnesium metal?

  1. It burns in oxygen with a dazzling white flame

  2. It reacts with cold water to form magnesium oxide and evolves hydrogen gas

  3. It reacts with hot water to form magnesium hydroxide and evolves hydrogen gas

  4. It reacts with steam to form magnesium hydroxide and evolves hydrogen gas

Answer: B

Image reaction of magnesium with cold water

Image Reaction of Magnesium with Cold Water

Image reaction of magnesium with cold water

Question 28:

Which among the following alloys contain mercury as one of its constituents?

  1. Stainless steel

  2. Alnico

  3. Solder

  4. Zinc amalgam

Answer: D

Image the Zinc amalgam

Image the Zinc Amalgam

Image the Zinc amalgam

Question 29:

Reaction between X and Y, forms compound Z. X loses electron and Y gains electron. Which of the following properties is not shown by Z?

  1. Has high melting point

  2. Has low melting point

  3. Conducts electricity in molten state

  4. Occurs as solid

Answer: B

Question 30:

The electronic configurations of three elements X, Y and Z are

X — 2, 8; Y — 2, 8, 7 and Z — 2, 8, 2. Which of the following is correct?

  1. X is a metal

  2. Y is a metal

  3. Z is a non-metal

  4. Y is a non-metal and Z is a metal

Answer: D

Image electronic configurations of some elements

Image Electronic Configurations of Some Elements

Image electronic configurations of some elements

Question 31:

Although metals form basic oxides, which of the following metals form an amphoteric oxide?

Answer: C

Question 32:

Generally, non-metals are not conductors of electricity. Which of the following is a good conductor of electricity?

  1. Diamond

  2. Graphite

  3. Sulphur

  4. Fullerene

Answer: B

Image the graphite

Image the Graphite

Image the graphite

Question 33:

Electrical wires have a coating of an insulting material. The material, generally used is

  1. Sulphur

  2. Graphite

  3. PVC

  4. All can be used

Answer: C

Copper coductor and insulation

Copper Coductor and Insulation

Copper coductor and insulation