Tag: hydrogen and its compounds

Quizzes (8) Questions (82)

Questions Related to hydrogen and its compounds

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

Which one of the following statements is correct about $D _{2}O$ and $H _{2}O$?

  1. $D _{2}O$ has lower dielectric constant than $H _{2}O$
  2. $NaCl$ is more soluble in $D _{2}O$ than in $H _{2}O$

  3. Both (a) and (b) are correct

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

D2O has a lower dielectric constant than H2O, which affects the solubility of ionic compounds. Consequently, many ionic salts, including NaCl, are less soluble in D2O than in H2O.

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

Which one of the following processes will produce hard water?

  1. Saturation of water with $CaCO _3$
  2. Addition of $Na _2SO _4$ to water.
  3. Saturation of water with $MgCO _3$
  4. Saturation of water with $CaSO _4$
Reveal answer Fill a bubble to check yourself
A,C,D Correct answer
Explanation

Hard water is water that has high mineral content (in contrast with "soft water"). Hard water is formed when water percolates through deposits of calcium and magnesium-containing minerals such as limestone, chalk and dolomite.
The following processes will produce hard water
1. saturation of water with $CaCO _3$
2. saturation of water with $MgCO _3$
3. saturation of water with $CaSO _4$
Hence options A,B & D are correct.

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

$D _2O$ differ in the following except:

  1. freezing point

  2. density

  3. ionic product of water

  4. its reaction with sodium
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The freezing point of water is $0 ^oC$, whereas the freezing point of heavy water is $3.8 ^0C$. 


At $20 ^0C$, the density of water is $0.9982$ g/mL, whereas the density of heavy water is $1.1056$ g/mL. 

Similarly, water and heavy water differ in the value of the ionic product. 

However, the chemical properties (such as reaction with sodium) of water are similar to that of heavy water due to the same electronic configuration.

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

Which of the following is not true?

  1. Hardness of water depends on its behaviour towards soap

  2. The temporary hardness is due to the presence of Ca and Mg bicarbonates

  3. Permanent hardness is due to the presence of soluble Ca and Mg sulphates

  4. Permanent hardness can be removed by boiling the water
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Permanent hardness is the hardness that cannot be removed by boiling. It is usually caused by the presence of calcium sulphate or magnesium sulphates or chlorides, nitrates of Ca, Mg in the water which does not precipitate out as the temperature increases.


Hence, option D is correct.

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

The boiling point of $D _{2}O$ is greater than $H _{2}O$. It is because:

  1. $D _{2}O$ has lower $K _w $ value
  2. $D _{2}O$ has a lower dielectric constant
  3. $D _{2}O$ is a associated liquid
  4. the molecular weight of $D _{2}O$ is greater than $H _{2}O$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

$D _2O$ has a somewhat higher boiling point because its molecular weight is about $(16+2+2=20)$ and $H _2O$ is about $(16+1+1=18)$.