Reaction with Oxygen

Q.

Copper and brass vessels are cleaned with lemon.give reason.

Q. Which of the following metals burn with a white dazzling light, with oxygen?

1. Potassium
2. Magnesium
3. Sodium
4. Aluminium

Q. Explain chemical reaction of metals.

Q. Which of the following metals form a protective layer of its oxide on reaction with atmospheric oxygen?

1. Potassium
2. Magnesium
3. Sodium
4. Aluminium

Q.

Metals, except Al and Zn, react with oxygen to form _______ oxides.

1. acidic

2. basic

3. amphoteric

4. neutral

Q.

Reaction of water on non metals

Q. How will you show that metal oxides are basic in nature? Give an example.

Q. Assertion [A]: Copper becomes dull in moist air.
Reason [R]: Copper is coated by a thin film of its basic copper carbonate formed in moist air.

1. Both A and R are true and R is the correct explanation of A.
2. Both A and R are true but R is not the correct explanation of A.
3. A is true but R is false.
4. A is false but R is true.
   

Q.

When metal reacts with oxygen metal oxide is formed.

1. True

2. False

Q. Which type of oxide is obtained when metal reacts with oxigen?

Q. How will you show that metal oxides are basic in nature? Give an example.

Q. Question 22

Paheli bought a statue made of copper. To her surprise, it acquired a dull green coating after a couple of months. Explain the reason.

Q. Copper becomes green when exposed to moist air for a long period. This is due to:

1. the formation of a layer of cupric oxide on the surface of copper
2. the formation of basic copper sulphate layer on the surface of the metal
3. the formation of a layer of cupric hydroxide on the surface of copper
4. the formation of a layer of basic carbonate of copper on the surface of copper

Q. Paheli bought a statue made of copper. To her surprise, it acquired a dull green coating after a couple of months. Explain the reason. ​

Q. What happen when the following nitrates are heated?

Q. Metals oxides are:

1. basic in nature
2. electrovalent (ionic) in nature
3. able to turn red litmus solution blue
4. all of these

Q.

What happens when metals react with oxygen?

Q.

Metals, except Al and Zn, react with oxygen to form _______ oxides.

1. neutral

2. acidic

3. basic

4. amphoteric

Q. When copper is exposed to moist air for a long time then a layer deposits on its surface due to corrosion. The colour of this layer is:

1. Green
2. Black
3. Grey
4. Brown

Q. Deterioration of a metal by chemical or electrochemical reaction with its environment is called _____.

1. corrosion
2. galvanization
3. painting
4. polishing

Q. A small piece of calcium metal is put into a trough containing water. There is effervescence and white turbidity is formed.
What do you observe when a few drops of red litmus solution are added to the turbid solution?

Q.

If a glass is blue in colour, which additional compound does it contain?

1. Cobalt compound
2. Nickel compound
3. Ferrous compound
4. Chromium compound

Q.

why is a copper vessel covered with a green coating in rainy season?