Tag: hydrogen and its compounds

Questions Related to hydrogen and its compounds

Ionic hydride among following is 

hydrides hydrogen and its compounds hydrogen chemistry

  1. $BeH _2$

  2. $NH _2$

  3. $CaH _2$

  4. $CuH _2$

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Correct Option: C

Hydrogen differ with alkali metals in the following aspect ?

hydrides hydrogen and its compounds hydrogen chemistry

  1. Formation of halides

  2. Formation of oxides

  3. Electronic configuration

  4. Atomicity

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Correct Option: A

Among $CaH _2, NH _3, NaH$ and $B _2H _6$, which are covalent hydrides?

hydrides hydrogen and its compounds hydrogen chemistry

  1. $NH _3$ and $B _2H _6$

  2. $NaH$ and $CaH _2$

  3. $NaH$ and $ NH _3$

  4. $CaH _2$ and $B _2H _6$

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Correct Option: A
Explanation:

$NH _3$ and $B _2H _6$ are the covalent hydrides and $CaH _2$ and $NaH$ are the ionic hydride.

$N$ and $B$ form covalent hydride as they have high electronegativity and small size.

Hydrogen is:

hydrides hydrogen and its compounds hydrogen chemistry

  1. electropositive

  2. electronegative

  3. both electropositive as well as electronegative

  4. neither electropositive nor electronegative

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Correct Option: C
Explanation:
Hydrogen is both electropositive as well as electronegative, as it forms hydrogen ion $H^+$ as well as hydride ion $H^-$.

Hydrogen readily combines with these elements?

hydrides hydrogen and its compounds hydrogen chemistry

  1. Na

  2. K

  3. Ca

  4. Zn

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Correct Option: A,B,C
Explanation:

${ H } _{ 2 }$ easily reacts with $Na, Ca, K$ as they are highly reactive metals and are placed at the top of the reactivity series.

${ 2Na }+{ H } _{ 2 }\rightarrow 2NaH$
$2K+{ H } _{ 2 }\rightarrow 2KH$
$Ca+{ H } _{ 2 }\rightarrow CaH _2$.

Boiling point of heavy water is:

chemistry hard water and soft water heavy water study of heavy water hydrogen and its compounds

  1. $3.82:^0C$

  2. $42:^{0}C$

  3. $100:^{0}C$

  4. $101.42:^{0}C$

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Correct Option: D
Explanation:

The boiling point of heavy water is $\displaystyle 101.42^oC $ which is higher than the boiling point of normal water $\displaystyle (100^oC) $ due to its higher molar mass.

When $SO _{3}$ treated with $D _{2}O$ , the products are:

chemistry hard water and soft water heavy water study of heavy water hydrogen and its compounds

  1. deutero sulphuric acid

  2. deuterium sulphuric acid

  3. deuterium and sulphuric acid

  4. $D _{2}SO _{3}$

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Correct Option: A
Explanation:
When $SO _3$ treated with $D _2O$ , the product is deutero sulphuric acid.
$SO _3+D _2O\rightarrow D _2SO _4$.

Heavy water is called so because:

chemistry hard water and soft water heavy water study of heavy water hydrogen and its compounds

  1. it has dissolved salts in it

  2. it is an oxide of heavy hydrogen

  3. it is a hydride of heavy oxygen

  4. all of the above

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Correct Option: B
Explanation:

Heavy water is called so because, it is the oxide of heavy hydrogen $(D _2$ or $ _1H^2)$.

Which of the following is not a deuterolysis reaction

chemistry hard water and soft water heavy water study of heavy water hydrogen and its compounds

  1. $SO _{3}+D _{2}O\rightarrow D _2SO _{4}$

  2. $CaC _{2}+2D _{2}O\rightarrow Ca(OD) _{2}+C _{2}D _{2}$

  3. $Mg _{3}N _{2}+6D _{2}O\rightarrow 3Mg(OD) _{2}+2ND _{3}$

  4. $AlCl _{3}3D _{2}O\rightarrow Al(OD) _{3}+3DCl$

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Correct Option: A
Explanation:

Option $A$ is not a deuterolysis reaction. It is not a chemical reaction at all. 

Deuterolysis reactions are reactions in which a salt reacts with heavy water to give a base and an acid.

Which of the following statement regarding $D _{2}O$ is correct?

chemistry hard water and soft water heavy water study of heavy water hydrogen and its compounds

  1. It is an isotope of hydrogen

  2. It is used as a bleaching agent

  3. It is used as a moderator in atomic reactors

  4. It is used as a coolant in atomic reactors

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Correct Option: C,D
Explanation:

$D _2O$  is used as a moderator in atomic reactors and as coolant in atomic reactors.

The chain reaction in a reactor is sustained by the free neutrons coming from one fission being absorbed by a Uranium nucleus, which then fissions itself. The probability of this absorbtion is increased if the neutrons are moving slowly. The purpose of the moderator is to slow the neutrons down. 
Lighter nuclei make better moderators than heavy nuclei. If a neutron were to hit an infinitely heavy nucleus, it would bounce off in a different direction with the same velocity. When a neutron hits a nucleus of atomic mass one head on, it comes to a complete stop. 
So, we want to use light nucleus. The reason water $(H _2O)$ is unsuitable is that it is likely to absorb the neutrons instead of slowing them down. The probability of water absorbing a neutron is more than $200$ times higher than the probability of deuterium (which already has a neutron) doing so.
Hence, options C and D are correct.