Jamb 2019

Question 1

Which of the following will give a precipitate with an aqueous solution of copper (I) chloride?

A. But-2-ene
B. But-1-ene
C. But-2-yne
D. But-1-yne

Answer 1

D

Question 2

What is the general formula for combustion reaction?

Answer 2

CxHy + (x + y/4)O2 → x CO2

+ y/2 H2O

Question 3

A certain hydrocarbon on complete combustion at s.t.p produced 89.6dm3
of CO2
and 54g of water. The hydrocarbon should be

A. C6H6
B. C4H10
C. C5H10
D. C4H6

Answer 3

D

Question 4

Hydrocarbons which will react with Tollen’s reagent conform to the general formula

Answer 4

CnH2n+1OH

Question 5

A synthetic rubber is not obtained from the polymerization of?

Answer 5

Hexane

Question 6

Burning magnesium ribbon in air removes which substance

Answer 6

Oxygen

Question 7

Which of the following is the best starting material for the preparation of oxygen? Heating of trioxonitrate (v) with

Answer 7

Lead

Question 8

Which metals is the most essential in the regulation of blood volume, blood pressure and osmotic equilibrium?

Answer 8

Sodium

Question 9

Which of the alkaline earth metals react more spontaneously with water?

Answer 9

Strontium

Question 10

When chlorine water is exposed to bright sunlight, the following products are formed

Answer 10

Hcl and o2

Question 11

Which process(es) is/are involved in the turning of starch iodide paper blue-black by chlorine gas?

Answer 11

chlorine oxidizes the iodide ion to produce iodine which attacks the starch to give the blue-black color

Question 12

Mention 3 neutral oxides

Answer 12

N2O, H2O and CO

Question 13

SO3 is not directly dissolved in water in the industrial preparation of H2SO4 by the contact process because

Answer 13

The reaction between SO3

and water is violently exothermic

Question 14

If acidified Potassium Dichromate(VI) (K2
Cr2
O7
) acts as oxidizing agent, color changes from

Answer 14

Orange to green

Potassium dichromate is an oxidising agent in organic chemistry. It is used to oxidize alcohols

Question 15

Mention three fact that air is a mixture

Answer 15

A. the constituents of air are in a fixed proportion by mass
B. it cannot be represented with a chemical formula
C. the constituents of air can be separated by physical by physical means

Question 16

What technique is suitable for separating a binary solution of potassium chloride and potassium trioxochlorate (V)?

Answer 16

Fractional crystallization

Question 17

Na2CO3 + 2HCl → 2NaCl + H2O + CO2

The indicator most suitable for this reaction should have a pH equal to

Answer 17

3

Question 18

Mention 2 gases used in the fountain experiment?

Answer 18

HCl and NH3

Question 19

Which of the following gases contains the least number of atoms at s.t.p?

A. 1 mole of butane
B. 4 moles of chlorine
C. 3 moles of ozone
D. 7 moles of argon

Answer 19

D

Question 20

What are isoelectric ion?

Answer 20

Two or more ions are said to be isoelectronic if they have the same electronic structure and the same number of valence electrons.

Question 21

Which sets of operation will completely separate a mixture of sodium chloride, sand and iodine?

Answer 21

addition of water, filtration, evaporation to dryness and sublimation

Question 22

Mention two substances that can liberate CO2

Answer 22

Carbonate and Ocala the

Question 23

is a substance which liberates CO2 on treatment with concentrated H2SO4. A warm solution of X can decolorize acidified KMnO4
. X is

Answer 23

H2C2O4

Question 24

How many alkoxyalkanes can be obtained from the molecular formula C4H10O?

Answer 24

3

Question 25

A solution X, on mixing with AgNO3 solution gives a white precipitate soluble in aqueous NH3 , a solution Y, when also added to X, also gives a white precipitate which is soluble when heated solutions X and Y respectively contain

Answer 25

Pb2+ and Cl-

Question 26

When the end alkyl groups of ethyl ethanoate are interchanged, the compound formed is

Answer 26

Methyl propanoate