Tag: chemistry

Questions Related to chemistry

Which of the following reactions is taking place resulting in discolouration of marble of the buildings like Taj Mahal?

chemistry planet earth acid deposition air and air pollution natural resources- air, water and land

  1. $CaC{ O } _{ 3 }+{ H } _{ 2 }S{ O } _{ 4 }\longrightarrow CaS{ O } _{ 4 }+{ H } _{ 2 }O+C{ O } _{ 2 }$

  2. $CaC{ O } _{ 3 }+{ H }Cl\longrightarrow CaC{ l } _{ 2 }+{ H } _{ 2 }O+C{ O } _{ 2 }$

  3. $CaC{ O } _{ 3 }+{ H } _{ 2 }O\longrightarrow Ca{ \left( OH \right) } _{ 2 }+C{ O } _{ 2 }$

  4. $CaC{ O } _{ 3 }\longrightarrow CaO+C{ O } _{ 2 }$

Show answer
Correct Option: A
Explanation:

Acid rain is the state when the pH of rain falls below 5.6.  Acid rain damages the buildings and statues as they dissolve and corrodes the heavy metals. This happens when sulphuric acid nitric acids in the polluted air react with calcite in marble, the calcite dissolves. It also dissolves metals from soils, rocks and sediments.  

Acid rain is produced by:

chemistry planet earth acid deposition air and air pollution natural resources- air, water and land

  1. excessive release of CO in air

  2. excessive release of $SO _{2}$ and $H _{2}S$ in air

  3. excessive release of $NO _{2}$ and $SO _{2}$ in air

  4. excessive release of $NH _{3}$ and $CO _{2}$ in air

Show answer
Correct Option: C
Explanation:

Acid rain is the state when pH of rain falls 5.6. It is mainly due to the presence of oxides of sulphur and nitrogen ( $ NO _2 $ and  $ SO _2 $ in the atmosphere. They are transported into the atmosphere by wind an other air currents. 

Which of the following statements is not true?

chemistry planet earth acid deposition air and air pollution natural resources- air, water and land

  1. Ammonia acts as sink for $NO _{x}$.

  2. Limestone acts as sink for $SO _{x}$

  3. The average residence time of NO is one month.

  4. $SO _{x}$ can be removed from flue gases by passing through a solution of citrate ions.

Show answer
Correct Option: C
Explanation:

Residence time means the lifetime amount of chemicals in the atmosphere divided by the rate at which the chemicals are eliminated from the atmosphere. The average residence time of NO is 0.5 to 2 days. 

Which of the following is not correctly matched?

chemistry planet earth acid deposition air and air pollution natural resources- air, water and land

  1. Water pollution - using synthetic detergents for washing clothes

  2. Photochemical smog - releasing gases produced by automobiles and factories

  3. Damaging ozone layer -using CFCS

  4. Acid rain - releasing pesticides and fertilizers in water

Show answer
Correct Option: D
Explanation:

The main component of acid rain are sulphuric acid, nitric acid and carbonic acid that are present in atmosphere due to cars and industries and factory waste. Human actions like using detergent, releasing pesticides and fertilizers in water lead to acid rain.

Mark the example which in not correctly matched?

chemistry planet earth acid deposition air and air pollution natural resources- air, water and land

  1. Air pollutants - Oxides of sulphur, nitrogen and carbon

  2. Particulate pollutants - Dust, mist fumes

  3. Global warming - Methane, ozone, CFCs

  4. Water soluble chemical pollutants - Oxides of nitrogen, carbon and sodium

Show answer
Correct Option: D
Explanation:

Water-soluble pollutants are detergents, fertilizers, oils from factories and industries, ammonical nitrogen etc. Whereas oxides of nitrogen, carbon, and sodium are air pollutants that cause gaseous pollution. 

Region/regions of the atmosphere where temperature decreases with altitude is/are:

chemistry planet earth acid deposition air and air pollution natural resources- air, water and land

  1. thermosphere

  2. stratosphere

  3. troposphere

  4. ozonosphere

Show answer
Correct Option: C
Explanation:
The temperature decreases with the altitude (height) in the lowest 10-20km of the atmosphere called the Troposphere because most of the solar radiation passes through the atmosphere with little or no effect.  That radiation is observed by the solid earth surface and is transferred to the air above the surface by conduction.

Match the column I with column II and mark the appropriate choice.

Column I Column II
(A) Peroxyacetyl nitrate (i) Global warming
(B) Polychlorinated biphenyls (ii) Photochemical smog
(C) Dioxides of carbon and sulphur (iii) Water pollutant
(D) IR active molecules (iv) Acid rain
chemistry planet earth acid deposition air and air pollution natural resources- air, water and land

  1. (A) $\rightarrow$ (ii), (B) $\rightarrow$ (iii), (C) $\rightarrow$ (iv), (D) $\rightarrow$ (i)

  2. (A) $\rightarrow$ (iii), (B) $\rightarrow$ (iv), (C) $\rightarrow$ (ii), (D) $\rightarrow$ (i)

  3. (A) $\rightarrow$ (iv), (B) $\rightarrow$ (ii), (C) $\rightarrow$ (iii), (D) $\rightarrow$ (i)

  4. (A) $\rightarrow$ (i), (B) $\rightarrow$ (iii), (C) $\rightarrow$ (ii), (D) $\rightarrow$ (iv)

Show answer
Correct Option: A
Explanation:

Peroxyacetyl nitrate is a secondary pollutant since they form in the atmosphere after the emission of primary pollutants. It is present in photochemical smog.

Surface water getting contaminated with PCB waste generally has high levels of PCBs in sediment, as the PCBs attach to organic matter. PCBs can be slowly released from the sediment into the water and evaporate into the air.

Sulfur dioxide another toxic chemical gas when combines with water and air, forms sulfuric acid, which is the main component of acid rain. Carbon dioxide in the air can dissolve in rainwater to form carbonic acid, $H _{2}CO _{3}$ and contributes to acid rain.

IR active molecules in the atmosphere can increase their vibrational energy by absorbing some of this infrared light, and thus increasing the temperature of the atmosphere resulting in Global warming.

The correct option is A.

Atmosphere of big cities is polluted most by :

chemistry natural resources- air, water and land acid deposition air and air pollution atmospheric pollution

  1. Automobile exhausts

  2. Radioactive fall out

  3. Household waste

  4. Pesticide residue

Show answer
Correct Option: A
Explanation:

The main source of pollution in metro cities is automobile exhausts. 


As greater the city, more the population which uses private transport.


Hence, increase in pollution is caused by automobile exhausts.


Therefore, option A is correct.

The pH of the acid rain is approximately:

chemistry planet earth acid deposition air and air pollution natural resources- air, water and land

  1. 5 to 6

  2. 2 to 3

  3. 6 to 7

  4. >10

Show answer
Correct Option: A
Explanation:

The pH of the acid rain is approximately 5-6.

Acid rain is due to :

chemistry planet earth acid deposition air and air pollution natural resources- air, water and land

  1. Combination of oxides of sulphur with rain water

  2. Combination of oxides of nitrogen with rain water

  3. Formation of $H _{2}SO _{4}$ and $HNO _{3}$

  4. All of the above

Show answer
Correct Option: D
Explanation:

When gases like $NO _2$ and $SO _3$ go into the atmosphere and react with water and form $H _2SO _4$ and $HNO _3$, these acids come along with rain water and hence it is known as acid rain.