Hydrogen - Online Test

Q1. In the process of obtaining pure de-mineralised water is passed initially through cation exchange, This makes the water
Answer : Option C
Explaination / Solution:

Cation exchange resin have exchangeable hydrogen ions which makes the water acidic.

Q2. Pure de-mineralised water is obtained by passing water through an anion exchange as a second process after passing it through a cation exchange. This makes the water
Answer : Option C
Explaination / Solution:

Cation exchange resin have exchangeable hydrogen ions which makes the water acidic while anion exchange resin have exchangeable hydroxide ion which makes the water basic. Passing water to anion exchange resin as a second process after passing through anion exchange resin makes the water neutral.

Q3. Hydrogen resembles halogens in many respects for which several factors are responsible. Of the following factors which one is most important in this respect?
Answer : Option B
Explaination / Solution:

Hydrogen, like the halogens, has one electron short of a complete outer shell and can form H- ions like Cl- and therefore forms ionic compounds with reactive metals – NaH similar in structure to NaCl. Hydrogen can gain one electron to form a duplet.Hydrogen also exists as a diatomic gas like fluorine and chlorine.

Q4.

Why does H+ ion always get associated with other atoms or molecules?


Answer : Option D
Explaination / Solution:

Loss of an electron from hydrogen atom results in a nucleus of very small size as compared to other atoms or ions.

H+ ion has exceptionally small size, so it can not exist freely.


Q5. Metal hydrides are ionic, covalent or molecular in nature. Among LiH, NaH, KH, RbH, CsH, the correct order of increasing ionic character is
Answer : Option B
Explaination / Solution:

As the size of cation increases ionic character also increases.

Q6. Temporary hardness It can be removed in boiling by precipitating
Answer : Option C
Explaination / Solution:

.Mg can be precipitate out in order to remove temporary hardness.

Q7. In Calgon’s method, one of the following chemical is used to remove hardness of water
Answer : Option C
Explaination / Solution:

Sodium hexametaphosphate is called calgon. Its molecular formula is (NaPO3)6 or Na6P6O18.

The addition of Calgon to hard water causes the calcium and magnesium ions of hard water to displace sodium ions from the anion of Calgon. This results in the removal of calcium and magnesium ions from hard water in the form of a complex with Calgon. The water is softened and sodium ions are released into water.


Q8. Which of the following hydrides is electron-precise hydride?
Answer : Option C
Explaination / Solution:

Electron precise hydride is the type of hydride in which the number of electrons present is equal to the number of electron required (octet or duplet). For example- CH4

CH4​ has no lone pair of electron or vacant orbital so it is an electron precise hydride.


Q9. The three isotopes of hydrogen in terms of chemical properties show one of the following properties
Answer : Option A
Explaination / Solution:

There are three isotopes of hydrogen namely, protium 1H1, deuterium 1Hor D and lastly tritium 1H3 or T.

Out of these three isotopes of hydrogen, only tritium is radioactive in nature which emits low energy b particles. As the electronic configuration of isotopes is same, they all have similar chemical properties. But they have a difference in their rates of reaction, this happens because of the different bond disassociation enthalpies.


Q10. Consider the reactions (A) 
Answer : Option B
Explaination / Solution:

 is an oxidizing agent in 1st reaction and Reducing agent in 2nd reaction.