Hydrogen

Question 1

Concentration of tritium

Answer 1

1 of 10^18 atoms of protium(hydrogen)

Question 2

What properties are common in isotopes of hydrogen.

Answer 2

They have same chemical properties because of same electronic configuration
Except the only difference is rate of rxn due to bond dissociation energy.
H2 < D2 < T2

They differ in physical properties because of large mass difference.

Question 3

Zn +NaOH –>

Answer 3

Na2ZnO2 + H2

Question 4

High purity hydrogen is obtained by?

Answer 4

Electrolysing barium hydroxide solution with nickel electrode.

It’s(h2) also obtained as a by product during electrolysis of brine soln
products are Cl2, NaOH, h2
(Brine soln –>water and dissolved salts

Question 5

★Rxn of hydrocarbon with steam gives?

Answer 5

★CO + H2 (water gas/syngas)
They (CO+ H2) ARE USED TO PREPARE METHANOL
★production of syngas from Coal and steam is called coal gasification.
C+ H20 –> CO + H2
Amount of hydrogen can be increased by rxn of product CO again with steam in presence of iron chromate [Fe2(CrO4 )3] as a catalyst.
CO + h2O –>CO2 +H2
(This is called water gas shift reaction) also called bosch processprocess. And CO2can be removed by rubbing with sodium arsenite.

Question 6

Fact !

Answer 6

The H-H bind dissociation enthalpy is the highest for a single bond between two atoms for any element.

Question 7

Which metal oxide can be reduced by Hydrogen.

Answer 7

Metal less active than iron including itself too reduces to metal in zero oxidation state and itself oxideses to H2O

CO +

Question 8

How is vanaspati ghee formed?

Answer 8

Hydrogenation of vegetable oils using nikel as catalyst gives edible days (margarine and vanaspati ghee)

Question 9

What is hydroformylation?

Answer 9

Reaction of olefins/alkene with hydrogen and Carbon monoxide with alkene/ olefins give aldehyde which further react with H2 to give alchohols.

Question 10

Important use of Dihydrogen

Answer 10

It is used to prepare methanol in presence of cobalt as catalyst.
CO + H2—> CH3OH

Question 11

Which group do not form hydrides.

Answer 11

Group 7 8 and 9
~And in grp 6 only chromium forms hydride.

Question 12

Angle between h2O molecule and O-H bond length in it.
No of oxygen atom attached to one oxygen atom and at distance of?

Answer 12

~104.5
~95.7pm
~each oxygen atom is surrounded by 4 oxygen atom and at a distance of 276pm.

Question 13

In CuSO4. 5h2O how many water molecule are hydrogen bonded.

Answer 13

Only one is hydrogen bonded rest are coordinated.

Question 14

Soft water vs hard water.

Answer 14

★Soft water is free from magnesium and calacium salts
★hard water- Temporary hardness is due to presence of bicarbonate of calcium and magnesium bicarbonates.
It’s forms scum with soap due to soap contains sodium sterate (C17H35COONa) and it reacts with hard water and forms precipitate.
It’s removed by boiling and clarks method.
★permanent hardness- contain chlorides and sulphates.
Removed by treatment with washing soda, calogons method(sodium hexameta phosphate Na6P6O18, ion exchange method and synthetic resin method.

Question 15

How is h2O2 industrially produced.

Answer 15

By autooxidation of 2 alkylantheaquinols

Question 16

Use of heavy water and it’s production.

Answer 16

It’s use as nuclear moderator in reactor.
It can be produced by exaustive elcteolysis of water and as a by product in some fertiliser industries.

Question 17

At high temp para hydrogen less/more stable than ortho hydrogen

Answer 17

Less stable

Question 18

Hydrogen peroxide is a oxidising agent or reducing agent.

Answer 18

Both reducing and oxidsing agent.

Question 19

Dihedral angle in hydrogen peroxide molecule is more in solid or gas phase.

Answer 19

Gas phase