Tag: hydrogen and its compounds

Quizzes (8) Questions (82)

Questions Related to hydrogen and its compounds

Multiple choice hydrides hydrogen and its compounds hydrogen chemistry

Ionic hydride among following is 

  1. $BeH _2$
  2. $NH _2$
  3. $CaH _2$
  4. $CuH _2$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

CaH2 is a classic example of an ionic (saline) hydride formed by an alkaline earth metal. BeH2 is covalent due to high charge density, and NH2 is not a standard binary hydride (NH3 is).

Multiple choice hydrides hydrogen and its compounds hydrogen chemistry

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

  1. $NH _3$ and $B _2H _6$
  2. $NaH$ and $CaH _2$
  3. $NaH$ and $ NH _3$
  4. $CaH _2$ and $B _2H _6$
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

Multiple choice hydrides hydrogen and its compounds hydrogen chemistry

Hydrogen is:

  1. electropositive

  2. electronegative

  3. both electropositive as well as electronegative

  4. neither electropositive nor electronegative
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Hydrogen is both electropositive as well as electronegative, as it forms hydrogen ion $H^+$ as well as hydride ion $H^-$.
Multiple choice hydrides hydrogen and its compounds hydrogen chemistry

Hydrogen readily combines with these elements?

  1. Na

  2. K

  3. Ca

  4. Zn
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
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.

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

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

Which of the following is not a deuterolysis reaction

  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. $AlCl _{3}3D _{2}O\rightarrow Al(OD) _{3}+3DCl$
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

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

  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
Reveal answer Fill a bubble to check yourself
C,D Correct answer
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.