Q1.When the solution of substance X is
added to a solution of potassium iodide, then a yellow solid separates out from
the solution.
(a) What do you think substance X is
likely to be?
(b) Name the substance which the yellow
solid consists of.
(c) Which characteristic of chemical
reaction is illustrated by this example?
(d) Write a balanced chemical equation
for the reaction which takes place. Mention the physical states of all the
reactants and products involved in the chemical equation.
Q2. When water is added gradually to a white solid
X, a hissing sound is heard and a lot of heat is produced forming a product Y.
A suspension of Y in water is applied to the walls of a house during white
washing. A clear solution of Y is also used for testing carbon dioxide gas in
the laboratory.
(a) What could be solid X? Write its chemical formula.
(b) What could be product Y? Write its chemical formula.
(c) What is the common name of the solution of Y which is used for testing
carbon dioxide gas?
(d) Write chemical equation of the reaction which takes place on adding water
to slid X.
(e) Which characteristic of chemical reactions is illustrated by this example?
Q3.When water is added gradually to a white solid X,
a hissing sound is heard and a lot of heat is produced forming a product Y. A
suspension of Y in water is applied to the walls of a house during white
washing. A clear solution of Y is also used for testing carbon dioxide gas in
the laboratory.
(a) What could be solid X? Write its chemical formula.
(b) What could be product Y? Write its chemical formula.
(c) What is the common name of the solution of Y which is used for testing
carbon dioxide gas?
(d) Write chemical equation of the reaction which takes place on adding water
to slid X.
(e) Which characteristic of chemical reactions is illustrated by this example?
Q4.A metal X forms a salt XSO4. The salt XSO4 forms
a clear solution in water which reacts with sodium hydroxide solution to form a
blue precipitate Y. Metal X is used in making electric wire and alloys like
brass.
(a) What do you think metal X could be?
(b) Write the name, formula and colour of salt XSO4.
(c) What is the blue precipitate Y?
(d) Write a chemical equation of the reaction which takes place when salt
XSO4reacts with sodium hydroxide solution. Give the state symbols of all the
reactants and products which occur in the above equation.
Q5.A compound ‘X’ is
used for drinking, has pH =7.Its acidified solution undergoes decomposition in
presence of electrictiy to produce gases ‘Y’ and ‘Z’ The volume of Y is double
than Z. Y is highly combustible whereas Z is supporter of combustion. Identify
X, Y & Z and write the chemical reactions involved.
Q6 A reddish
brown vessel developed a green colored solid X When left open in air for a long
time. When reacted with dil 
, it forms a blue colored solution along
with brisk efficient due to colourless & odourless gas Z. X decomposes to
form black colored oxide Y of a reddish brown metal along with gas Z, Identify
X, Y, & Z.
Q7.A strip of metal X is
dipped in a blue coloured salt solution YSO4. After some time, a layer of metal
Y from the salt solution is formed on the surface of metal strip X. Metal X is
used in galvanisation whereas metal Y is used in making electric wires. Metal X
and metal Y together form an alloy Z.
(a) What could metal X be?
(b) What could metal Y be?
(c) Name the metal salt YSO4.
(d) What type of chemical reaction takes place when metal X reacts with salt
solution YSO4? Write the equation of the chemical reaction involved.
(e) Name the alloy Z.
Q8.Two metals X and Y form the salts XSO4 and Y2SO4,
respectively. The solution of salt XSO4 is blue in colour whereas that of Y2SO4
is colourless. When barium chloride solution is added to XSO4 solution, then a
white precipitate Z is formed alongwith a salt which turns the solution green.
And when barium chloride solution is added to Y2SO4 solution, then the same
white precipitate Z is formed alongwith
colourless common salt solution.
(a) What could the metals X and Y be?
(b) Write the name and formula of salt XSO4.
(c) Write the name and formula of salt Y2SO4.
(d) What is the name and formula of white precipitate Z?
(e) Write the name and formula of the salt which turns the solution green in
the first case.
.
Q9. solutions X and Y are tested with universal
indicator. Solution X turns orange whereas solution Y turns red. Which of the
solutions is a stronger acid?
Q10) The pH values of six solutions A to F are given
below:
A = 0, B = 11, C = 6, D = 3, E = 13, F = 8
Which of the above solutions are (i) acids (ii) alkalis?
(b) Name the acids or alkalis used to make (i) car batteries (ii) explosives
(iii) soaps (iv) fertilisers.
Q11.Hydrochloric acid reacts with a metal X to form
a gas Y which burns with a 'pop' sound. Sodium hydroxide solution also reacts
with the same metal X (on heating) to form the same gas Y.
(a) Name X and Y
(b) Write the chemical equation of the reaction of metal X with (i)
hydrochloric acid, and (ii) sodium hydroxide solution.
Q12..A compound ‘X’ is used for drinking, has pH
=7.Its acidified solution
undergoes decomposition in presence of electrictiy
to produce gases ‘Y’ and ‘Z’ The volume of Y is double than Z. Y is highly
combustible whereas Z is supporter of combustion. Identify X, Y & Z and
write the chemical reactions
involved.
Q13..An aqueous solution of metal nitrate P reacts
with sodium bromide
solution to form yellow ppt of compound Q which is
used in photography. Q
on exposure to sunlight undergoes decomposition
reaction to form metal
present in P along with reddish brown gas. Identify
P &Q. Write the chemical reaction & type of chemical reaction.
Q14..A reddish brown vessel developed a green
colored solid X When left open
in air for a long time. When reacted with dil , it
forms a blue colored
solution along with brisk efficient due to
colourless & odourless gas Z. X
decomposes to form black colored oxide Y of a
reddish brown metal along
with gas Z, Identify X, Y, & Z.
Q15.
A substance X used for coating iron articles is added to a blue solution of
a reddish brown metal Y,the color of the
solution gets discharged Identify X and
Y & also the type of reaction
Q16.A
compound ‘X’ is used for drinking, has pH =7.Its acidified solution undergoes
decomposition in presence of electrictiy to produce gases ‘Y’ and ‘Z’ The
volume of Y is double than Z. Y is highly combustible whereas Z is supporter of
combustion. Identify X, Y & Z and write the chemical reactions involved.
Q17..An
aqueous solution of metal nitrate P reacts with sodium bromide solution to form
yellow ppt of compound Q which is used in photography. Q on exposure to
sunlight undergoes decomposition reaction to form metal present in P along with
reddish brown gas. Identify P &Q. Write the chemical reaction & type of
chemical reaction.
Q18..Bhawana
took a pale green substance A in a test tube. And heated it over the flame of a
burner. A brown colored residue B was formed along with evolution of two gases
with burning smell of sulphur. Identify A & B. Write the chemical reaction
involved.
Q19.A metal salt MX when
exposed to light splits upto to form metal M and gas X2. Metal M is used to
make ornaments whereas gas X2 is used in making bleaching powder. The salt MX
is used in black & white photography.
(a) Identify the metal M and gas X2
(b)Identify MX.
(c) Write down the chemical reaction when salt MX is exposed to
sunlight.
Q20. A metal strip X is dipped in blue coloured salt solution
YSO4. After some time a layer of metal ‘Y’ is formed on metal strip X. Metal X
is used in galvanization whereas metal Y is used for making electric wires.
(a) What could be metal ‘X’ and ‘Y’ ?
(b) Name the metal salt YSO4.
(c) What type of chemical reaction takes place between X and
YSO4? Write the balanced chemical equation.
Q21.Equal
length of magnesium ribbon are taken in two test tubes ‘A’ and ‘B\ H2SO4 is
added to test tube ‘A’ and H2CO3 in the test tube ‘B’ in equal amounts:(a)
Identify the test tube showing vigorous reaction.(b) Give reason to support
your answer.(c) Name the gas liberated in both the tubes. How will you prove
its liberation?(d) Write chemical
equations for both reactions.(e) Out of the two acids taken above(i)
which one will
have lower pH value.(ii) lowerH+
concentration respectively.
Q22..An aqueous solution of metal
nitrate P reacts with sodium bromide
solution to form yellow ppt of
compound Q which is used in
photography. Q on exposure to
sunlight undergoes decomposition
reaction to form metal present in P
along with reddish brown gas.
Identify P &Q. Write the
chemical reaction & type of chemical reaction.
Q23.(i) Explain why is hydrochloric
acid a strong acid and acetic acid, a weak acid. How
can it be verified?(ii) Explain why
aqueous solution of an acid conducts electricity.(iii)
Q24.You have four solutions A, B, C
and D. The pH of solution A is 6, B is 9, C is 12 and D is
7,a) Identify the most acidic and
most basic solutions.(b) Arrange the above four
solutions in the increasing order
of H+ ion concentration.(c) State the change in colour
of pH paper on dipping in solution
C and D.
Q25(a) Identify the compound of
calcium which is yellowish white powder and is used for disinfecting drinking
water. Write its chemical name and formula. How is it manufactured? Write the
chemical equation for the reaction involved. Also list two other uses of the
compound.(b) Write the balanced chemical equation of chlor-alkali
process.
Q26.Salt ‘A’ commonly used
in bakery products on heating gets converted into another salt ‘B which itself
is used for the removal of hardness of water and a gas ‘C’ is evolved. The gas
‘C’ when passed through lime water, turns it milky. Identify A, B and C.
Q27.In one of the
industrial processes used for the manufacture of sodium hydroxide, a gas ‘X’ is
formed as by-product. The gas ‘X’ reacts with lime water to give a compound ‘Y’
which is used as a bleaching agent in chemical industry. Identify ‘X’ and ‘Y’ giving
the chemical equation of the reactions involved.
Q28.A metal carbonate (X) on reacting with an acid gives a gas
which when passed through a solution (Y) gives the carbonate back. On the other
hand, a gas (G) that is obtained at anode during electrolysis of brine is
passed on dry substance (Y). It gives a compound (Z), used for disinfecting
drinking water. Identity X, Y, G and Z.
Q29.A sulphate salt of Group 2 element of the Periodic Table is
a white, soft substance which can be moulded into different shapes by making
its dough. When this compound is left in open for some time, it becomes a solid
mass and cannot be used for moulding purposes. Identify the sulphate salt. Why
does it show such a behaviour ? Give the reaction involved.
Q30.A
metal carbonate X on treatment with a mineral acid liberates a gas which when
passed through an aqueous solution of a substance Y on reaction with the gas
obtained at anode during electrolysis of brine gives a compound Z which can
decolourise coloured fabrics. The compounds X, Y and Z respectively
Q31.A silvery
white metal X reacts with water at room temperature to produce a water soluble
compound Y and a colourless gas Z . The reaction is highly exothermic and the Z
catches fire immediately during the reaction. The solution of Y in water on
reacting with stoichiometric amount of dilute solution of hydrochloric acid
gives a solution of pH = 7 The compounds X , Y and Z
332.(a) Three acidic solutions A, B and C have pH = 0, 3 and 5 respectively.
(i) Which solution has highest concentration of H+ ions?
(ii) Which solution has the lowest concentration of H+ ions?
(b) How concentrated sulphuric acid can be diluted? Describe the
process.
Q33. A compound P forms the enamel of teeth. It is the hardest substance
of the body. It doesn’t dissolve in water but gets corroded when the pH is
lowered below 5.5.
(a) Identify the compound P.
(b) How does it undergo damage due to eating chocolate and sweets? What
should we do to prevent tooth decay?
