Science : Ch 03 – Metals and Non-metals

Which of the subsequent quality is generally not shown by metals?

The solution of one of the following compounds will not conduct electricity. This compounds is:

Generally, metals react with acids to give salt and hydrogen gas. Which of the following acids does not give hydrogen gas on reacting with metals (except Mn and Mg)?

The composition of aqua-regia is:

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?

In the given reaction, Al₂O₃ + NaOH → …X… + H₂O. What is element X?

2 ml each of conc. HCl, HNO₃, and a mixture of conc. HCl and conc. HNO3 in the ratio of 3:1 were taken in test tubes labelled as : A, B and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B but the metal got dissolved in test tube C. The metal could be:

1. AI
2. Au
3. Cu
4. Pt

Hydrogen gas is not evolved when a metal reacts with nitric acid because

When calcium metal is added to water, the gas evolved does not catch fire but the same gas evolved on adding potassium metal to water catches fire.

Metal that can be cut by knife

A Metal that exists in liquid state at room temperature

Non-metal that can exist in diferent forms

Give the formula of the stable binary compounds that would be formed by the combination of following pair of elements: K and O₂

Name a metal which is highly malleable

When a metal X is treated with cold water, it gives a basic salt Y with molecular formula XOH (molecular mass = 40) and liberates a gas Z which easily catches fre. Identify X, Y and Z.