Question

B. Short Answer Type Questions:

1. Complete the following reactions-

i) Fe + H2O

ii) Ca + H2O

iii) K + H2O

2. Generally when metals are treated with mineral acids ,

hydrogen gas is liberated but when metals ( except Mn and

Mg) treated with dil. HNO3, hydrogen is not liberated, why?

3.You are given a hammer , a battery , a bulb, wires and a

switch.

a)How could you use them to distinguish between samples

of metals and non- metals?

b)Assess the usefulness of these tests in distinguish between

metals and non- metals?

4. What are amphoteric oxides? Give two examples of

amphoteric oxides with reactions .

5.Give reasons-

a) Copper is used to make hot water tanks and not steel.

b) Gold and silver are used to make jewellery.

c) Sodium, potassium and lithium are stored under oil.

6. Mettalic oxides of zinc, magnesium and copper were

heated with the following metals-

Metals Zinc Magnesium Copper

Zinc oxide

Magnesium

oxide

Copper oxide

In which cases will you find displacement reactions taking

place?

7. Give an example of a metal which is-a) the most malleable

b) the best conductor of heat c) not found in free state.

8. Which important properties of aluminium are responsible

for its great demand in industry?

9. When a metal X is treated with cold water, it gives a basic

salt with molecular formula XOH and liberated a gas Z,

which easily catches fire. Identify X,Y and Z and also write

the reaction involved.

10. In the given structure, write:a)Chem.formula:______

b) Metal:_______ , Non- metal:______

c) Anion:_______ , Cation: _____​

Answer 1

2) HNO3 is a strong oxidising agent. It oxidises the H2 produced to water and itself gets reduced to nitrogen oxide(N2O, NO, NO2). but Mg and Mn react with very dilute HNO3 to evolve H2 gas

4) metal oxide react with both acid as well as base to produce salt and water are known as amphoteric oxide. eg: ZnO + HCl > ZnCl2 + H2O

ZnO + NaOH > Na2ZnO2 + H2O

5) a) Copper are pure metal and have free ions as compared to steel.

b) Gold and silver have the nature of malleability, ductility and lustrous.

c) sodium, potassium are more reactive in air and water

9) X- K, Na

Y - KOH, NaOH

Z - H2