+91-8076753736[email protected]
logo
logo
-->

Hydrogen

Question
CBSEENCH11006949
Wired Faculty App

What is ‘demineralised water’ and how can it be obtained?

Solution
Water which does not contain cations and anions is called demineralised water. It is obtained by passing hard water first through cation exchange resin and then through anion exchange resin.

During the cation exchange process, H+ exchange for Na+, Mg2+, Ca2+ and other cations present in water.
bold 2 bold RH subscript bold left parenthesis bold s bold right parenthesis end subscript bold space bold plus bold M subscript bold left parenthesis bold aq bold right parenthesis end subscript superscript bold 2 bold plus end superscript bold rightwards arrow over leftwards arrow bold space bold MR subscript bold left parenthesis bold s bold right parenthesis end subscript bold space bold plus bold 2 bold H subscript bold left parenthesis bold aq bold right parenthesis end subscript superscript bold plus bold. bold. bold. bold 1

In anion exchange process OH- exchange for anions such as Cl-, HCO3- etc.present in water.
bold RNH subscript bold 2 bold space bold left parenthesis bold s bold right parenthesis end subscript bold space bold plus bold H subscript bold 2 bold O subscript bold left parenthesis bold l bold right parenthesis end subscript bold space bold rightwards arrow over leftwards arrow bold RNH subscript bold 3 superscript bold plus bold. bold OH to the power of bold minus bold RNH subscript bold 3 superscript bold plus bold. bold OH to the power of bold minus bold left parenthesis bold s bold right parenthesis bold plus bold X subscript bold left parenthesis bold aq bold right parenthesis end subscript superscript bold minus bold space bold rightwards arrow over leftwards arrow bold space bold RNH subscript bold 3 superscript bold plus bold. bold X to the power of bold minus bold space bold plus bold space bold OH to the power of bold minus bold left parenthesis bold aq bold right parenthesis bold space bold space bold space bold. bold. bold. bold. bold 2

ions liberated in reaction 1 and 2 neturlaize each other, thus forming water.
bold H to the power of bold plus bold space bold plus bold OH to the power of bold minus bold space bold rightwards harpoon over leftwards harpoon bold space bold H subscript bold 2 bold O

Some More Questions From Hydrogen Chapter

Hydrogen is the lightest gas. Still its use in filling balloons has been discarded. Why?

Hydrogen forms both H+ ion and H- ion. Explain.

What is the molecular mass of a compound formed when tritium is burnt in air?

Out of H2 and D2 which has higher boiling point and why?

Give one use of liquid hydrogen. 

Why dihydrogen (H2) is not preferred for filling of balloons and airships?

Mock Test Series

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation