Tag: chemistry

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Multiple choice chemistry changes around us effects of oxidation reactions in daily life corrosion of metals electroplating and its application

Iron nails rust fast when used for fixing plates or strips of aluminium on a building. Similarly, a water pipe made of iron corrodes faster when connected to a pipe of copper. This happens because of the?

  1. Greater wetting of iron

  2. Easier flow of electrons to iron

  3. Higher rusting power of iron

  4. Chemical reduction of iron
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

This is due to higher rusting power of iron.

When iron pipe is connected to copper corrosion is caused by self induced current created. The current is generated due to difference in electrical potential. The water act as a weak electrolyte.

Multiple choice chemistry changes around us effects of oxidation reactions in daily life corrosion of metals electroplating and its application

The presence of $CO _2$ in the atmosphere results in:

  1. rusting.

  2. dusting.

  3. electroplating.

  4. freezing.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The presence of $CO _2$ in the atmosphere will do iron oxide rusting. When a drop of water hits an iron object, two things begin to happen almost immediately. 

First, the water, a good electrolyte, combines with carbon dioxide in the air to form a weak carbonic acid, an even better electrolyte. As the acid is formed and the iron dissolved, some of the water will begin to break down into its component pieces - hydrogen and oxygen. 
The free oxygen and dissolved iron bond into iron oxide, in the process freeing electrons.

Multiple choice chemistry changes - physical and chemical effects of oxidation reactions in daily life corrosion of metals electroplating and its application

The tarnishing of silver ornaments in atmosphere is due to:

  1. $Ag _{2}O$
  2. $Ag _{2}S$
  3. $Ag _{2}CO _{3}$
  4. $Ag _{2}SO _{4}$
Reveal answer Fill a bubble to check yourself
A,B Correct answer
Explanation

The tarnishing of silver ornaments in atmosphere is due to formation of silver oxide $Ag _{2}O$ and silver sulphide $Ag _{2}S$.

$2Ag\, +\, \displaystyle 
\frac{1}{2}{O _{2}}\, \rightarrow\, Ag _{2}O$

$2Ag\, +\, H _{2}S\, \rightarrow\, Ag _{2}S\, +\, H _{2}$

Hence, option A and B are correct.

Multiple choice chemistry changes - physical and chemical effects of oxidation reactions in daily life corrosion of metals electroplating and its application

Which metal is protected by a layer of its own oxide?

  1. $Al$
  2. $Ag$
  3. $Au$
  4. $Fe$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Aluminium in air is ordinarily protected by a molecule-thin layer of its own oxide. This aluminium oxide layer serves as a protective barrier to the underlying aluminium itself and preventing chemical reactions with the metal.

Multiple choice chemistry soil- our life the soil soil erosion (geo) soil erosion, soil conservation and uses of soil

In which of the following soil the ratio of large particles are high?

  1. Clayey soil

  2. Sandy soil

  3. Muddy soil

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In sandy soil, the ratio of large particles are high as the sand is the large particle in soil than the clay and slit. So in sandy soil sand particles are more
Hence option B is correct.

Multiple choice chemistry soil- our life the soil soil erosion (geo) soil erosion, soil conservation and uses of soil

Which of the following characteristic property of clay soil make it useful to grow plants?

  1. Retain water and moisture

  2. Do not retain water and moisture

  3. Holds lot of sand

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The particles size is very tiny and they are compact thereby retaining water and moisture, which helps the plants to grow well.