Question

The major threat to Taj Mahal is:
A.Acid rain
B.Hydrogen peroxide
C.Both a and b
D.None of the above

Answer 1

Hint: Air pollution is increasing day by day and due to that, Taj Mahal is changing its colour from white to yellow. This is creating a problem because Taj Mahal is one of the seven wonders of the world and so a tourist attraction. It is one of many historical cultural sites of India. Its corrosion will lead to decrease in the tourism of India.

Complete answer:
-The air around us contains many gases like nitrogen, oxygen, carbon-dioxide,etc. When they are in the appropriate proportion, then the balance of nature is not disturbed.
-Nowadays, automobiles and factory chimneys are emitting huge amounts of carbon-dioxide, sulfur oxides and nitrogen oxides leading to air pollution.
-When sulfur and nitrogen from chimneys react with the atmospheric oxygen, they form their respectives oxides.
\[\begin{align}
  & S\left( s \right)+{{O}_{2}}\left( g \right)\to S{{O}_{2}}\left( g \right) \\
 & 2NO\left( g \right)+{{O}_{2}}\left( g \right)\to 2N{{O}_{2}}\left( g \right) \\
\end{align}\]
-They form sulfur and nitrogen oxides of the form $S{{O}_{X}}$ and $N{{O}_{X}}$ . They are basically $S{{O}_{2}},S{{O}_{3}},N{{O}_{2}}$ and NO.
-When rainfall occurs, these gases combine with the rainwater and form acids. The reaction of oxides with rainwater can be shown as:
\[\begin{align}
  & S{{O}_{2}}+{{H}_{2}}O\to {{H}_{2}}S{{O}_{3}} \\
 & S{{O}_{3}}+{{H}_{2}}O\to {{H}_{2}}S{{O}_{4}} \\
 & 2N{{O}_{2}}+{{H}_{2}}O\to HN{{O}_{2}}+HN{{O}_{3}} \\
\end{align}\]
These acids are sulfurous acid, sulfuric acid, nitrous acid and nitric acid respectively.
-Taj Mahal is made of marble. Marble is a metamorphic rock which contains calcite formed by limestone.
-The acids formed during rainwater fall down along with the rainwater. When they hit the marble of Taj Mahal, they dissolve the calcite as it reacts with the acids.
-This leads to the corrosion of the marble and hence is the reason for the yellow sheen of the Taj Mahal.
-The exposed surface thus becomes roughened as the material is removed and the carvings of the monument are lost.

Therefore, the correct answer is acid rain which is option A.

Note:
In 2019, Uttar Pradesh govt. has planned the procurement of electric buses to cut the vehicular emissions. Use of CNG is made compulsory. Various private sectors have also volunteered to help reduce air pollution in the area. Factories located near the Taj Mahal are constantly monitored regarding the effluents thrown out by their chimneys.
Also, a 30 million dollar project is proposed by the Massive Fund to eliminate more than 90 percent of plastic waste in Agra. The Yamuna clean-up project is also active.