Tag: chemistry

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Multiple choice chemistry air and water pollution control environmental impact: global warming green house effect geobiochemical cycle

The gas that is not considered as a 'green house gas' is:

  1. $CO _2$
  2. $CH _4$
  3. $O _2$
  4. $O _3$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The gases in the atmosphere that absorb radiation are known as "greenhouse gases" (sometimes abbreviated as GHG) because they are largely responsible for the greenhouse effect. The most significant greenhouse gases are water vapor $(H _2O)$, carbon dioxide $(CO _2)$, methane $(CH _4)$  and nitrous oxide $(N _2O)$ and ozone $(O _3)$. While oxygen $(O _2)$ is the second most abundant gas in our atmosphere, $O _2$ does not absorb thermal infrared radiation to cause green house effect.


Hence, the correct option is C.

Multiple choice chemistry air and water pollution control environmental impact: global warming green house effect geobiochemical cycle

The two gases making the highest relative contribution to the greenhouse gases are:

  1. $CO _{2}$ and $CH _{4}$
  2. $CH _{4}$ and $N _{2}O$
  3. $CFC{s}$ and $N _{2}O$
  4. $CO _{2}$ and $N _{2}O$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Highest contribution to green house gases are $CO _2 $  $60$% and $CH _4$  $20$% which absorbs more of the infrared rays and UV rays and causes global warming.  

Multiple choice chemistry air and water pollution control environmental impact: global warming green house effect geobiochemical cycle

Identify the non-Green House Gas (GHG) from the following

  1. Methane

  2. Nitrous oxide

  3. Sulphur hexafluoride

  4. Carbon monoxide
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Carbon monoxide is a colorless, odorless, and tasteless gas that is slightly less dense than air. Carbon Monoxide and other reactive gases Carbon monoxide (CO) is not considered a direct greenhouse gas, because it does not absorb terrestrial thermal IR energy strongly enough. 

Multiple choice chemistry air and water pollution control environmental impact: global warming green house effect geobiochemical cycle

Greenhouse gas is produced if oxygen is combined with :

  1. $\displaystyle Na$
  2. $\displaystyle S$
  3. $\displaystyle { H } _{ 2 }$
  4. $\displaystyle Ne$
  5. $\displaystyle C$
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

$C + O _2 \rightarrow CO _2$
$CO _2$ is a green house gas, which act as blanket in earth atmosphere, and cause Green house effect.
Green House Effect:
The Earth gets energy from the sun in the form of sunlight. The Earth's surface absorbs some of this energy and heats up. That's why the surface of a road can feel hot even after the sun has gone down—because it has absorbed a lot of energy from the sun. The Earth cools down by giving off a different form of energy, called infrared radiation. But before all this radiation can escape to outer space, greenhouse gases in the atmosphere absorb some of it, which makes the atmosphere warmer. As the atmosphere gets warmer, it makes the Earth's surface warmer, too.

Multiple choice chemistry chemistry of non-metals oxides of elements simple oxides oxygen

Which of the following are basic oxides? 
$Mn _2O _7$ ,$V _2O _3$, $V _2O _5$, $Cr _2O _3, CrO$ 

  1. $Mn _2O _7$ and $V _2O _3$
  2. $V _2O _3$ and $CrO$
  3. $CrO$ and $Cr _2O _3$
  4. $V _2O _5$ and $V _2O _3$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

As metallic character decreases as we move across the period then basicity of oxides increases.

Also, we know oxide in lowest oxidation state of element is more basic. So, in $V _2O _3$ and $CrO$, oxidation state of $V$ and $Cr$ are $+3$ and $+2$ respectively which is lowest among others.

Multiple choice chemistry chemistry of non-metals oxides of elements simple oxides oxygen

Select the correct option regarding the properties of dioxygen?

  1. Dioxygen never reacts with metals.

  2. Dioxygen is diamagnetic in nature.

  3. Combination of dioxygen with other elements is highly exothermic process.

  4. Dioxygen liquefies at 55 K and freezes at 90 K.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Dioxygen reacts with metals and is paramagnetic. It combines with other elements to form oxides where the reaction is highly exothermic.

Multiple choice chemistry p-block elements oxides of elements simple oxides oxygen

A group of acidic oxide is:

  1. $CrO _{3},Mn _{2}O _{7}$
  2. $ZnO,Al _{2}O _{3}$
  3. $CaO,ZnO$
  4. $Na _{2}O,Al _{2}O _{3}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

here,${ CrO } _{ 3 }$ are acidic oxides

${ CrO } _{ 3 }+{ H } _{ 2 }O\longrightarrow { H } _{ 2 }{ CrO } _{ 4 }\ { Mn } _{ 2 }{ O } _{ 7 }+{ H } _{ 2 }O\longrightarrow { 2HMnO } _{ 4 }$