Home
Class 12
CHEMISTRY
A certain salt (X) gives the following t...

A certain salt `(X)` gives the following tests :
(a) Its aqueous solution is alkaline to litmus.
(b) On strong heating. It sweels to give a glassy bead.
( c) When conc `H_(2) SO_(4)` is added to a hot concentrated solution of `(X)`, white crystals of a weak acid separates out. Identify `(X)` and write down the chemical equations for reaction at steps `a, b` and `c`.

Text Solution

Verified by Experts

Since the salt (X) smells on heating to give a glassy material, it seems to be borax, `Na_(2)B_(4)O_(7)`, a well known compound showing this property. This is also in accordance with the fact that its aqueous solution is alkaline to litmus and its reaction with conc. `H_(2)SO_(4)` to give crystals of a weak acid. `H_(3)BO_(3)` (Boric acid ) Thus (X) is `Na_(2)B_(4)O_(7).10H_(2)O`. Chemical reactions are
(i) `underset("Borax")(Na_(2)B_(4)O_(7))+7H_(2)Orarr underset("alkaline")ubrace(underset("Storng base")(2NaOH)+underset("Weak acid")(4H_(3)BO_(3)))`
(ii) `Na_(2)B_(4)O_(7) overset("heat")rarr underset("(glassy bead)")(2NaBO_(2))+B_(2)O_(3)`
(iii) `Na_(2)B_(4)O_(7)+H_(2)SO_(4)+5H_(2)Orarr Na_(2)SO_(4)+underset("Boric acid")(4H_(3)BO_(3))`
Promotional Banner

Topper's Solved these Questions

  • PRINCIPLES OF QUALITATIVE ANALYSIS

    AAKASH INSTITUTE|Exercise Assignment (SECTION G)|5 Videos

  • POLYMERS

    AAKASH INSTITUTE|Exercise ASSIGNMENT (SECTION-D)|13 Videos

  • REDOX REACTIONS

    AAKASH INSTITUTE|Exercise ASSIGNMENT SECTION - D|10 Videos

Similar Questions

Explore conceptually related problems

A certain salt X gives the following results: Its aqueous solution is alkaline to litmus.

An aq. Solution of a salt (x) is alkaline to litmus. On strong heating, it swell up to give a glassy material. When conc. H_(2)SO_(4) is added to a concentrated solution of x, white crystal of a weak acid separates out. Hence compound (x) is

A certain salt X gives the following results: (i) Its aqueous solution is alkaline to litmus. (ii) It swells up to a galssy material Y on strong heating. (iii) When conc. H_(2)SO_(4) is added to a hot solution of X, white crstals of an acid Z separate out. Write equations for all the above reactions and identify x,y and Z.

A certain salt X gives the following results: It swells up to a glassy material Y on strong heating.

A certain salt X gives the following results: When conc. H_(2)SO_(4) is added to a hot solution of X, white crystal of an acid Z separates out. Write equations for all the above reactions and idenfity X, Y and Z.

Aqueous solution of salt of strong base and weak acid