The name of unreactive gas is

Solution
An inert gas is unreactive with elements.
Hydrogen is unreactive gas.
The important metal used with iron to produce stainless steel is

Solution
Chromium makes the stainless steel.
Coal is regarded as the worst environmental pollutant when burnt because its burning releases large amount of
1. Carbon dioxide 2. Sulphur dioxide
3. Nitrogen oxides (NOX) 4. Methane
Which of the above statements are true?
Which of the following affects biodiversity?

Solution
Environmental Pollution, Ocean acidification and climate change affects biodiversity.
One of the following is an international agency working for the protection of the environment
Threefifths of twothirds of threesevenths of a number is 150. What is 60% of that number?

Solution
Let the number be x.
∴ Threefifths of twothirds of threesevenths of number = 150\(∴xtimes frac{3}{5}times frac{2}{3}times frac{3}{7}= 150\)
\(x=frac{35 times 150}{6}= 875\)
∴ 60% of x=^{60}⁄_{100}×875= 525
If p = ^{3}⁄_{5},q = ^{7}⁄_{9},r = ^{5}⁄_{59} then which of the following inequality is true ?

Solution
∵p= ^{3}⁄_{5} = 0.60,
q= ^{7}⁄_{9} = 0.777
r= ^{7}⁄_{5} = 0.714
∴ The inequality p < r < q is true
The average age of 100 workers in a factory is 36.5. The average age of the men is 45 and that of the women is 28. The number of women working in the factory is

Solution
Let the number of women workers be x.
∴ Then, the number of men workers = (100x)
Now, according to the question,
∴ 100 × 36.5 = (100  ×) × 45 + x × 28
⇒ (45  28) × = 4500  3650
\(∴x=frac{850}{17}=50\)
men and 3 boys can do a piece of work in 10 days, while 3 men and 2 boys can do the same work in 8 days. In how many days can 2 men and 1 boy do the work?

Solution
According to the question,
∴ Work of (2 men + 3 boys) for 10 days
= Work of (3 men + 2 boys) for 8 days
⇒ 20 men + 30 boys = 24 men + 16 boys
= (24  20) men = (30  16) boys
⇒ 2 men = 7 boys
⇒ 2 men + 1 boy = (7 + 1) boys = 8 boys
and 2 men + 3 boys = (7 + 3) boys = 10 boys
(2 men + 3 boys) ie 10 boys can do the
work in = 10 days
∴ (2 men + 1 boy) ie, 8 boys will do the same
work in =\(frac{10times 10}{8}=frac{25}{2}\)= 12.5 days
A bus can complete a journey in 6 hours if it travels at 60 km/hr. At what speed (km/hr) the bus must travel in order to complete the journey 1 in 9 hours?

Solution
Let the required speed of the bus be x km/hr
∴ Distance of journey = Speed × Time
= x × 9 hours = 60 km/hr × 6 hours
\(∴x=left ( frac{60×6}{9} right )=40 km/hour\)
Sikh army was called
Whom do we call “The Iron Man of India”?
An instrument that records earthquakes is
The second largest producer of cotton textiles in India is
A State cannot exist without
What is the colour of fresh domestic sewage?
Which one of the following nonmetal is not a poor conductor of electricity?
Which of the following is one of the major components of acid rain?

Solution
Sulphuric acid is one of the major components of acid rain.
The compounds affecting the ozone layer of the atmosphere are

Solution
The compounds affecting the ozone layer of the atmosphere are chlorofluorocarbons.
Ozone layer prevents humans from skin cancer.
Which statement is most correct for air?