Tag: chemistry

Quizzes (490) Questions (9892)

Questions Related to chemistry

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

Assertion (A): The oxides of nitrogen and sulphur combine with rainwater and come down as acid rain.
Reason (R): Acid rains cause depletion of ozone layer.

  1. Both A and R are true and R is the correct explanation of A

  2. Both A and R are true but R is not correct explanation of A

  3. A is true and R is false

  4. A is false and R is true
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Below are few properties of acid rain:
1) Acid rains are obtained due to oxides of nitrogen & sulphur.
2) Nitric acid and sulphuric acid in the atmosphere dissolve in rain water and come down to earth as acid rain. 
3) It may have a pH less than 5.6
4) There is no relation of acid rain with ozone layer.

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

Which of the following gases will not cause acid rain?

  1. $SO _2$
  2. $NO _2$
  3. $CO _2$
  4. $O _3$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Sulphur present in any fuel combines with oxygen and forms $SO _2$ in the combustion chamber. $SO _2$ when emitted into the atmosphere, it oxidizes to form $SO _3$. It is soluble in water in the clouds and forms $H _2SO _4$ (Sulphuric acid).

$S+O _2 \rightarrow SO _2 +\dfrac {1}{2} O _2 \longrightarrow SO _3+H _2O\rightarrow H _2SO _4$

Most of the $NO _x$ emitted in the form in the forms of $NO$.
This $NO$ oxidised in the atmosphere to form $NO _2$.
$NO _2$ is soluble in water and form $HNO _3$ (Nitric Acid).

$NO+\dfrac {1}{2}O _2\rightarrow NO _2+H _2O\rightarrow HNO _3$ 
                       
Carbon divide reacts with water to form carbonic acid. Carbonic acid then dissociates to give the hydrogen ion $(H^+)$ and the hydrogen carbonate ion $(HCO _3^-)$. The ability of $H _2CO _3$ to deliver $H^+$ classifies this molecule as acid.

$CO _2 +H _2O\longrightarrow H _2CO _3$

$H _2CO _3 \longrightarrow H^++HCO _3^-$

For $O _3$,
$O _3+$Ultraviolet $\rightarrow O+O _2$

$O+O _3\rightarrow 2O _2$

Net Reaction: $2O _3+ UV\rightarrow 3O _2$

It does from any acidic component therefore $O _3$ will not cause acid rain.
Multiple choice chemistry planet earth acid deposition air and air pollution natural resources- air, water and land

Acid rains are produced by:

  1. excess ${NO} _{2}$ and ${SO} _{2}$ from burning fossil fuels
  2. excess production of ${NH} _{3}$ by industry and coal gas

  3. excess release of carbon monoxide by incomplete combustion
  4. excess formation of ${CO} _{2}$ by combustion and animal respiration
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Acid rain is primarily caused by the emission of sulfur dioxide (SO2) and nitrogen oxides (NOx) from the combustion of fossil fuels, which then react with water in the atmosphere.

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

Temperature of troposphere decreases with altitude. This is because of_____.

  1. high pressure of air

  2. gases present in air

  3. low density of air

  4. all of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Generally, temperatures decrease with increasing height because the atmosphere distributes itself according to gravity.

In the troposphere, the temperature generally decreases with altitude. The reason is the troposphere's gases absorb very little of the incoming solar radiation. Instead, the ground absorbs this radiation and then heats the tropospheric air by conduction and convection.
Multiple choice chemistry planet earth acid deposition air and air pollution natural resources- air, water and land
The production of dihydrogen gas via water gas shift reaction,
 
$CO(g) + H _2O (g) \xrightarrow {\Delta/Catalyst} CO _2(g) + H _2(g).$

The $CO _2$ gas is removed by scrubbing with solution of 

  1. sodium arsenite

  2. calcium oxide

  3. sodium phosphate

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

The water-gas shift reaction (WGSR) describes  the reaction of carbon monoxide and water vapour to form carbon dioxide and hydrogen (the mixture of carbon monoxide and hydrogen is known as water gas)

$CO(g) + H _2O (g) \xrightarrow {\Delta/FeCrO _4} CO _2(g) + H _2(g).$

The carbondioxide obtained in the above reaction is removed by scrubbing with solution of sodium arsenite.

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

Which of the following are responsible for causing acid-rain?

  1. Oxides of sulphur and carbon dioxide.

  2. Oxides of nitrogen and carbon monoxide.

  3. Hydrogen sulphide and carbon dioxide.

  4. Oxides of sulphur and nitrogen.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Acid rain caused by emissions of sulphur dioxide and nitrogen oxide, which react with water molecules in the  atmosphere to produce corresponding acids.


Oxides of sulphur + water $\rightarrow$ Sulphuric acid

Oxides of Nitrogen + water $\rightarrow$ Nitric acid

Option D is correct.

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

Low visibility in cold weather is due to:

  1. formation of fossil fuel

  2. unburnt carbon particles or hydrocarbons suspended in air

  3. lack of adequate power supply

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Smog is a dark brown or greyish smoky mist that occurs in cold weather. It is formed by unburnt carbon particles or hydrocarbons suspended in the air. It is a visible indication of air pollution. Smog not only reduces visibility but is highly suffocating and harmful to human beings, animals and plants.


Hence, the correct option is $B$

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

Acid rain is caused by:

  1. deforestation
  2. $CO _2$
  3. $CO$

  4. oxides of sulphur and nitrogen
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Acid rain is caused by oxides of sulphur and nitrogen. 
The sulphur dioxide gas released during burning of coal and oxides of nitrogen released during combustion of petrol dissolve in rain water and form acids such as sulphuric acid and nitric acid. these acids drop down with rain which makes rain acidic.