ammonia

Question 1

state the observation

burning of ammonia in air

Answer 1

a greenish-yellow flame is observed

Question 2

state the observation

when ammonia is burnt in an atmosphere of excess oxygen

Answer 2

ammonia burns with a pale blue flame in the atmosphere of excess oxygen

Question 3

state the observation

excess of chlorine gas is reacted with ammonia gas

Answer 3

a yellow explosive liquid is formed (nitrogen trichloride)

Question 4

state the observation

ammonia is passed through the copper oxide

Answer 4

black copper oxide changes to red copper

Question 5

state the observation

excess of ammonia is passed through an aqueous solution of lead nitrate

Answer 5

a white precipitate is produced which is insoluble even in an excess of ammonia

Question 6

state the observation

a piece of moist red litmus paper is placed in a gas jar of ammonia

Answer 6

it turns blue

Question 7

state the observation

neutral litmus solution is added to an alkaline solution

Answer 7

it turns blue

Question 8

this gas is used as a reducing agent in reducing copper oxide to copper

Answer 8

ammonia

Question 9

gas produced when excess ammonia reacts with chlorine

Answer 9

nitrogen

Question 10

alkaline gas which gives dense white fumes with HCl

Answer 10

ammonia

Question 11

the gas that can be oxidized to sulphur

Answer 11

hydrogen sulphide

Question 12

an oxidizing agent which does not contain any sulphur

Answer 12

chlorine gas

Question 13

warming ammonium sulphate with sodium hydroxide solution

Answer 13

ammonia

Question 14

drying agent used to dry ammonia

Answer 14

CaO

Question 15

passing dry ammonia over heated copper oxide gives ______

Answer 15

copper

Question 16

ammonia can be obtained by adding water to _______

Answer 16

magnesium nitride

Question 17

ammonium nitrate is used in ___________________

Answer 17

preparing explosives

Question 18

with excess of chlorine what does ammonia form

Answer 18

NCl3 [nitrogen trichloride]

Question 19

why is liquid nitrogen employed in refrigerator

Answer 19

because it has a high latent heat of vaporization so it takes high amount of heat from the surroundings resulting in the fall of temperature

Question 20

why is ammonia soluble in water

Answer 20

this is because it is a polar molecule

Question 21

nesseler’s reagent is an alkaline solution of _____

Answer 21

K2HgI4 [Potassium tetraiodomercurate(II)]

Question 22

what temperature is catalytic oxidation of ammonia carried out at ?????

Answer 22

800 degrees celcius

Question 23

where is the nitrogen used in haeber’s process obtained from

Answer 23

fractional distillation of air

Question 24

how is ammonia gas collected

Answer 24

downward displacement of air

Question 25

why is ammonia used as a cleaning agent

Answer 25

ammonia solution emulsifies fat and grease so that they can be removed without leaving any residue

Question 26

ammonia solution is used as a laboratory reagent to identify metal ions

Answer 26

aqueous solution of ammonia can precipitate insoluble hydroxide of metals from their salt solutions hence it is used in the analytical analysis of the salts in the labaratory

Question 27

ammonia is present in sewage water

Answer 27

this because ammonia is produced due to bacterial decomposition of urea [NH2CONH2] present in urea

Question 28

solution of ammonia contains hydroxide ions

Answer 28

since ammonia turns red litmus solution blue it reacts with water to form salt and water

Question 29

ammonia cannot be collected over water

Answer 29

ammonia is extremely soluble in water and cannot be collected over water

Question 30

though ammonia nitrite readily gives nitrogen on heating, a mixture of ammonium chloride and sodium nitrite in water is heated to prepare nitrgoen in the labaratory

Answer 30

ammonium nitrite cannot be stored even at room therefore nitrogen is obtained by heating ammonium chloride and sodium nitrite

Question 31

magnesium nitride reacts with water to liberate _____ and _________

Answer 31

ammonia and magnesium hydroxide

Question 32

what is labaratory bench reagent

Answer 32

it is a dilute solution of liquor ammonia

Question 33

why is dry or liquid ammonia neutral to litmus

Answer 33

ammonia is a covalent compound therefore in the absence of ions dry or liquid Ammonia has no effect on litmus

Question 34

state the purpose of liquifycing ammonia produced in haeber's process

Answer 34

the ammonia procuced is liquifiedto seperate it from uncombined nitrogen and hydrogen

Question 35

write the equation for Haeber's process that forms ammonia

Answer 35

N2 + 3H2 --> 2NH3 (reversible) {200-900atm and 450-500 degrees celcius and catalyst Fe and Mo}

Question 36

what test does Nessler's reagent give with ammonium salts

Answer 36

when ammonium compound is added to colourless Nessler's reagent a brown colour is observed

Question 37

why is acidic drying agent not used for drying ammonia

Answer 37

because acidic drying agents such as H2SO4 react with ammonia

Question 38

how does the solubility of ammonia vary with its temperature

Answer 38

its solubility decreases with an increase in temperature

Question 39

how will you separate ammonia from uncombined N2 and H2

Answer 39

by liquefication by dissolving in water

Question 40

why is catalyst chamber provided with a heat exchanger

Answer 40

this is so that the outgoing ammonia gas and the unreacted gases exchange their heat with the incoming nitrogen and hydrogen

Question 41

which is more dense, ammonia or hydrogen chloride how is it collected

Answer 41

hydrogen chloride is denser than ammonia upward displacement of air

Question 42

what happens when ammonia and HCl gas react write the equation

Answer 42

NH3 + HCl --> NH4Cl

Question 43

give 2 evidences to show that the solution of ammonia in water contains hydroxide ions

Answer 43

i) solution of ammonia is alkaline towards litmus ii) the solution of ammonia precipitates insoluble metal hydroxide

Question 44

what is the reactant used in the preapration of ammonia gas

Answer 44

Mg3N2 + H2O

Question 45

what is the drying agent used in the preparation of ammonia gas

Answer 45

quicklime (Cao)

Question 46

what is the method of collection used in the preparation of ammonia gas

Answer 46

downward displacement of air

Question 47

large scale use of ammonia

Answer 47

manufacture of nitric acid by ostwalds process

Question 48

what properties of ammonia make it a source of hydrogen

Answer 48

--> ammonia can be liquified and transported easily and on decomposition gives hydrogen --> liquid hydrogen is dangerous to transport in cylinders

Question 49

how is ammonium chloride prepared

Answer 49

neutralisation

Question 50

when ammonium chloride is heated what reaction does it undergo

Answer 50

thermal dissociation

Question 51

what does heating ammonia chloride with sodium hydroxide produce

Answer 51

ammonia

Question 52

why is ammonia nitrate not used in the preparatuon of ammonia

Answer 52

- -> it is explosive in nature | - -> it decomposes giving nitrous oxide and water vapour

Question 53

how do you find out if the jar is full of ammonia gas

Answer 53

bring a rod dipped in HCL to the mouth of the jar for which ammonium chloride will be formed