Question

Q1 how can we ascertain the acidic nature of rain
i) by touching
ii) by tasting
iii) by the use of antacid
iv) by litmus

Q2- acid rain causes damage to



i) large status and marble sculpture
ii) plants and animals
iii) growth of plants
iv) all of the tese​

Answer 1

Explanation:

tan

2

(x)−sin

2

(x)

=

cos

2

(x)

sin

2

(x)

−sin

2

(x)

=sin

2

(x)(

cos

2

(x)

1−cos

2

(x)

)

=sin

2

(x)(

cos

2

(x)

sin

2

(x)

)

=sin

2

(x)tan

2

(x)

Compare both LHS and RHS and clearly

\begin{gathered} \frac{1}{ \ \cos {}^{2} (x) - sin {}^{2} (x) } \\ \\ = \frac{1}{ \cos(2x) } = \sec(2x) \neq \: \tan {}^{2} (x) \end{gathered}

cos

2

(x)−sin

2

(x)

1

=

cos(2x)

1

=sec(2x)



=tan

2

(x)

Answer 2

1. The acidic nature of rain can be ascertained by litmus. Thus, the correct option is (iv).

2. Acid rain causes damage to large statues and marble sculptures, plants and animals, growth of plants, etc. Thus, the correct option is iv) all of the these

Explanation:

• The acidic nature of rain can be determined by testing the pH of rainwater.
• The pH of rainwater can be tested by a pH meter or by the use of litmus paper.
• Litmus paper is used to test the pH of a solution by observing the change in the colour of the litmus paper.
• Blue litmus paper turns red when it comes in contact with acidic solutions and remains blue with neutral and basic solutions.
• On the other hand, the red litmus paper remains red with acidic and neutral solutions and turns blue when it comes in contact with basic solutions.
• Acid rain causes damage to statues, buildings, monuments and marble sculptures.
• It also causes depletion of nutrients of the soil, increases the acidity of soil and reduces the fertility of the soil. Therefore, it hampers the growth of plants.
• It also causes damage to animals and plants.