Corrosion

Q. <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> <!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> What is a displacement reaction?

Q.

Corrosion in case of iron is known as:

1. Rancidity

2. Rusting

3. Combination

4. Reduction

Q.

Which amongst the following metals does not undergo corrosion?

1. Iron

2. Zinc

3. Copper

4. Gold

Q.

Corrosion of metal is a highly desirable process.

1. True
2. False

Q.

Formation of rust when iron is exposed to moist air is called ________.

1. Double displacement

2. Displacement

3. Corrosion

4. Neutralization

Q. Limewater turns milky when carbon dioxide gas is passed through it due to the formation of _________.​

Q.

__is the gradual destruction of materials by chemical reaction with their environment.

Q.

Mention two harmful/damaging effects of corrosion.

Q. The correct formula of rust is

1. $F{e}_2{O}_3$
2. $F{e}_3{O}_4$
3. $F{e}_2{O}_3.x{H}_{2}O$
4. $F{e}_3{O}_4.x{H}_{2}O$

Q. A numismatist (coin collector) has been collecting gold coins, silver coins, and copper coins for a long time. One day he observed a black coating on silver coins and green coating on copper coins.

Which chemical process is responsible for these coatings. Also name the chemical formula of the black and green coatings.
[2 Marks]

Q. Observe the given experimental set-up carefully.
In which test tubes rusting of iron nails will not take place?

1. Q and R only
2. All of these
3. P and R only
4. P and Q only

Q. how does electroplating prevent corrosion?

Q.

What effect does salt have on the rate of corrosion?

1. Remains same

2. None of these

3. Slows down the corrosion.

4. Speeds up the corrosion.

Q.

Corrosion of iron in presence of oxygen leads to reddish brown powder (Iron oxide). This process is called __ of iron.

Q.

Which of the following elements will not undergo corrosion?

1. Magnesium
2. Potassium
3. Phosphorus
4. Calcium

Q. A metal in the powdered form reacts very slowly with the boiling water, but it decomposes steam.
Name the metal.​

Q.

Which of the following metal oxide is referred as rust?

1. Cuprous oxide

2. Ferric oxide

3. Cupric oxide

4. Ferrous oxide

Q. Balance the following chemical equation.
$Na\left(s\right)+H_{2}O\left(l\right)\to NaOH\left(aq\right)+H_2\left(g\right)$

Q. Metal with high concentration of $O_2$ on its surface acts as :

1. an anode
2. a cathode
3. an electrolyte
4. none of these

Q. The formula for rust is:

1. $F{e}_2{O}_3.x{H}_{2}O$
2. $FeO.x{H}_{2}O$
3. $F{e}_2{O}_4.x{H}_{2}O$
4. $F{e}_2{O}_2$