Tag: chemistry

Questions Related to chemistry

What happens when oxygen reacts with alkaline pyragallol?

chemistry air and atmosphere carbon dioxide - an oxide of carbon component of air - carbon dioxide oxides of non metal

  1. dark brown colour is seen

  2. it forms a complex compound

  3. black colour is seen

  4. both A and B

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Correct Option: D
Explanation:

When oxygen reacts with alkaline pyragallol solution,dark brown colour is seen and it forms a complex compound.

The chemicals used for testing oxygen are:

chemistry air and atmosphere carbon dioxide - an oxide of carbon component of air - carbon dioxide oxides of non metal

  1. nitric oxide

  2. alkaline pyragallol

  3. both A and B

  4. none of the above

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Correct Option: C
Explanation:

The chemicals used for testing oxygen are nitric oxide and alkaline pyragallol solution.

What happens when $NO$ mixes with oxygen?

chemistry air and atmosphere carbon dioxide - an oxide of carbon component of air - carbon dioxide oxides of non metal

  1. Greenish white fumes are seen

  2. No effect on NO

  3. Reddish brown fumes comes out

  4. Bluish green fumes comes out

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Correct Option: C
Explanation:

When $NO$ mixes with oxygen, reddish brown fumes of $NO _2$ appears.$2 NO _{(g)} + O _{2(g)}\rightarrow 2NO _{2(g)}$

The splint is burnt and is inserted in a jar containing oxygen. What will happen to the glowing splint?

chemistry air and atmosphere carbon dioxide - an oxide of carbon component of air - carbon dioxide oxides of non metal

  1. the splint goes off

  2. no effect

  3. rekindles glowing splint

  4. it changes its colour

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Correct Option: C
Explanation:

Oxygen is a supporter of combustion. Introducing the burning splint will rekindle it.

If dissolved ______ is not present, the aquatic life would die.

chemistry air and atmosphere carbon dioxide - an oxide of carbon component of air - carbon dioxide oxides of non metal

  1. Oxygen

  2. Nitrogen

  3. Hydrogen

  4. None of these

Show answer
Correct Option: A
Explanation:

Dissolved oxygen means the  free or  non-compound oxygen present in water or in  other liquids. Dissolved oxygen is important to many forms of life including fish, bacteria and plants. These organisms use oxygen in respiration, similar to organisms on land. Fishes obtain oxygen for respiration through their gills, while plant life and phytoplankton require dissolved oxygen for respiration when there is no light for photosynthesis.

So the given statement If dissolved oxygen is not present, the aquatic life would die.

In the following reaction, $O^{18}$ is in what?
$2MnO _4{^-}+5H _2O^{18} _2+6H^+\rightarrow 2Mn^{2+}+8H _2O+5O _2$ 

chemistry air and atmosphere carbon dioxide - an oxide of carbon component of air - carbon dioxide oxides of non metal

  1. $H _2O$

  2. $O _2$

  3. Both $(A)$ and $(B)$

  4. None of these

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Correct Option: B
Explanation:
${ 2MnO } _{ 4 }^{ - }+5{ H } _{ 2 }{ O } _{ 2 }^{ 18 }+6{ H }^{ + }\longrightarrow 2{ Mn }^{ 2+ }+8{ H } _{ 2 }O+5{ O } _{ 2 }$
In the following reaction ${ O }^{ 18 }$ labelled isotope is in ${ O } _{ 2 }$.

When $H _2S$ burns completely in oxygen, the products include:
(1) S
(2) $SO _2$
(3) $H _2O$

chemistry air and atmosphere carbon dioxide - an oxide of carbon component of air - carbon dioxide oxides of non metal

  1. If 1, 2 and 3 are correct

  2. If only 1 and 2 are correct

  3. If only 2 and 3 are correct

  4. If only 1 is correct

  5. If only 3 is correct

Show answer
Correct Option: C
Explanation:

$H _2S$ burns completely in the presence of oxygen as:

${ 2H } _{ 2 }S+{ 3O } _{ 2 }\rightarrow { 2SO } _{ 2 }+2{ H } _{ 2 }O$

Give the characteristic test for $O _{2}$ gas.

chemistry air and atmosphere carbon dioxide - an oxide of carbon component of air - carbon dioxide oxides of non metal

  1. Lime water test

  2. Potassium permanganate test

  3. Burning candle test

  4. All of these

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Correct Option: C
Explanation:

Characteristic test for oxygen ($O _{2}$) can be performed on the basis that oxygen supports burning. Therefore if we bring a burning candle near the source of oxygen, the intensity of the flame increases.

Dry ice on heating converts into:

chemistry air and atmosphere carbon dioxide - an oxide of carbon component of air - carbon dioxide oxides of non metal

  1. liquid

  2. do not convert

  3. gas

  4. none of the above

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Correct Option: C
Explanation:
Dry ice is the solid state of the gas carbon dioxide.when the pressure under which dry ice is decreased to 1atm it gets converted directly to gas.
Dry ice sublimes on heating i.e. it converts directly into gas.

The density of carbon dioxide is around:

chemistry air and atmosphere carbon dioxide - an oxide of carbon component of air - carbon dioxide oxides of non metal

  1. $2.98 {kg}/{{m}^{3}}$

  2. $1.98 {kg}/{{m}^{3}}$

  3. $5.0 {kg}/{{m}^{3}}$

  4. $10.0 {kg}/{{m}^{3}}$

Show answer
Correct Option: B
Explanation:

Carbon dioxide is colorless. At low concentrations, the gas is odorless. At higher concentrations it has a sharp, acidic odor. At standard temperature and pressure, the density of carbon dioxide is around $1.98  {kg}/{{m}^{3}}$, about $1.67$ times that of air.