SALT LAKE SCHOOL(E.M.

)
HALF YEARLY
CLASS - 10
CHEMISTRY
___________________________________________________________________________
Full Marks = 80 TIME= 2 HRS

Section A is compulsory. Attempt any four questions from SectionB.

The intended marks for questions or parts of questions are given in brackets[].

SECTION- A (Attempt all questions from this Section.)

1. For part (i) to (xv), select the correct answer from the choices A, B, C and D which are
given. Write only the letter corresponding to the correct answer. Incorrect combinations
will be considered as complete wrong answers. [15]
I. The element with highest ionisation potential:
A) Fluorine B) Chlorine C) Helium
II. Arrange the following elements in increasing order of number of valence electron
A) C,N,O,F B) O,C,N,F C) C,N,F,O
III. The radii of F,F-,O and O-2 are in the order:
A)O-2>F->F>O B) O-2>F->O>F C) F->O-2>F>O
IV. The gas that turns acidified K2Cr2O7 solution from orange to green:
A) Hydrogen sulphide B) Sulphur trioxideC) Sulphur dioxide
V. Fuming nitric acid contains:
A) 98%HNO3 B)50%HNO3 C)68% HNO3
VI. The yellow explosive compound when ammonia with chlorine
A) NH4Cl B) NCl3 C) HCl
VII. Total number of electrons present in 1.6 g methane
A) 10 B) 6.023X1023 C) 6.023X1024
VIII. Co-ionic bond is present in
A)Hydronium ion B) Ethane C) Sodium Chloride
IX. 1H3 is an isotope of hydrogen in the modern periodic table,it will:
A)be placed before hydrogen B) placed at the same position as hydrogen C) not have
a position in the periodic table.
X. Ethyne burns in excess air in:
A) brilliant white B) sooty flame C) blue coloured flame
XI. Ethoxyethane and ethanol are:
A) position isomers B) functional isomers C) chain isomers
XII. A compound with empirical formula XY2, has a vapour equal to its empirical
formula weight,its molecular formula is:
A) XY2 B) X3Y6 C)X2Y4
XIII. IUPAC name of methyl acetylene
A) Propyne B) Ethyne C) Butyne
XIV. The % of nitrogen in urea is:
A) 23.33% B) 20% C)46.66%

XV. V2O5 is used as a catalyst in preparation of:

A) Nitrogen B) Sulphur dioxide C) Sulphur trioxide

2. i) The diagram shows an experiment setup for the laboratory preparation of an acid. [5]
a) Name A(a liquid),B(a solid)and C(a liquid).(Do not give formula)
b) Write a balanced chemical equation for the above preparation.
c)Why is all glass apparatus used?
d)The acid prepared is yellow in colour.Why?
e) How is this colour removed?
ii) Match the Column I with Column II (Matching Column II with I will not be accepted)
[5]

Column I Column II

i)Solvent for Phosphorous A) CnH2n

ii)Olefins B) Ethanoic acid

iii)Paraffins C)CnH2n+2

iv)Gaseous polar compound D)HCl

v)Pickle steel E) SO2

iii) Complete the following by choosing the correct answers from the bracket:
[5]

a)The element above magnesium in the same group would be expected to have the
________[smaller/ larger] atomic radii.
b)H-C-H bond angle in ethene __________ (120/180).

c)Ammonia in liquid form is _______[neutral/basic]

d)__________[Ethane/Methane] is also known as marsh gas.
e) The colour of methyl orange becomes yellow because of higher concentration of
_____________[hydronium/hydroxide] ion.
 iv)Identify the following:(Write name only) [5]

a)An organic compound that contains three carbons and 3 -OH groups.
b) The agent that is an acceptor of electrons.
c) Self linking property of an element to form long chains or rings.
d)A covalent compound in which the shared pair of electrons are not at equal
distance between atoms.
e) The law that helps to determine the molecular formula of a gaseous compound.

v) a) Draw the structural diagram for the following compounds: [5]

1.Butyraldehyde
2.Diethyl ketone
3.4-methylpentan-2-ol
b) Give IUPAC name of the following organic compounds:

1.

2.

SECTION-B(Attempt any four questions)

3. (i) Identify the reactant and write the balanced equation for the following: [2]

Hydrochloric acid reacts with compound Q to give a salt sodium

chloride,water,sulphur and sulphur dioxide.

(ii) Identify the anion present in each case of the following compounds: [2]

a) When barium chloride solution is added to a solution of B, a white

 precipitate is insoluble in dilute hydrochloric acid.

b) When dilute sulphuric acid is added to compound D, a gas is produced

which turns lime water milky but has no effect on acidified potassium
permanganate solution.

iii) Write the products and balance the equation: [3]

a) Phosphorous + HNO3(conc.) =

b) Cane Sugar + H2SO4(conc.) =

c) NH3 + CO2=

iv.a)Calculate: [2]

i) A gas cylinder is filled with hydrogen and it holds 5g of a gas.The

same cylinder holds 85g of gas X under the same T & P.Calculate
the vapour density of gas X.

ii) Give the empirical formula of CH3COOH.

b) Calculate the number of “H” atoms in 1 mole H2SO4 [1]

4. (a) Arrange the following as per instructions given in the brackets: [5]
(i) Mg,Cl,Na,S,Si(decreasing order of atomic size)
(ii) Cs,Na,Li,K,Rb(increasing metallic character)
(iii) Na,Mg,Cl,S,Si(increasing ionisation potential)
(iv) K,Pb,Ca,Zn(increasing reactivity)
(v) F,Cl,Br,I(non-metallic character)

(b) Fill in the blanks using the correct options: [3]

(i) Metal have ------ ionisation potential. (low/ high)
(ii) Elements with atomic number 59 will be placed in group_______(3/5)
(iii) Group 15 elements are called ----- metals (pnictogens / chalcogens)

(c) Draw the electron dot structure of the following: [2]

a) Ammonium ion
b) Carbon tetrachloride
5.a) Draw different isomers (2 each) with suitable IUPAC names having the following formulae
[4]
(i) Pentane (chain)
(ii) Pentene (position)

(b) Alkynes undergo________________[addition/substitution]reaction. [1]

(c) Give two important uses of ethanol. [1]
(d) Write equations for: [4]
(i) Preparation of ethanol by hydration of C2H4.
(ii) Preparation of acetic acid from ethanol.
(ii)Ethyne is treated with a cold dilute alkaline KMnO4 solution.
(iv)Preparation of ethyl ethanoate from ethanol.

6. (a) With respect to Haber’s process answer the following:

(a) Temperature of the reaction

(b) Catalyst used

(c) Balanced equation for the reaction occurring [3]

(b) (a)
Ranjana wants to prove that ammonia is a reducing agent. To demonstrate this, she passes ammonia
gas over heated copper oxide. What will she observe?

(b) Write a balanced chemical equation for the above reaction.

Question:7
i) If a compound has an empirical formula CH2O and its molecular weight is 180,
calculate its molecular formula.
[2]
ii) Solve: 1250cc of oxygen was burnt with 300cc of ethane(C2H6).Calculate the
volume of the unused oxygen and the volume of the carbon dioxide formed.
[2]
2C2H6 + 7O2 = 4CO2 + 6H2O
iii) Galena,when roasted,reacts according to the following equation:
[3]
2PbS + 3O2 = 2PbO + 2SO2
Calculate:
a) The weight of PbO formed when 478g of PbS is roasted.
 b) The weight of PbS required to produce 5.6 litres of SO2 at S.T.P.
c) The number of moles of oxygen required at the same time.
Question 8
i) Draw the electron dot structure of the following:
[2]
c) H3O+
d) CH4
ii) Distinguish between the following as directed:
[2]
a) Sodium Carbonate and sodium sulphate by using dilute HCl
b) Ammonium Sulphate and Sodium sulphate by using calcium hydroxide

iii) Elements A,B,C and D have atomic numbers 20,8,6,17.Without identifying

the elements, answer the following questions:
What type of bonding is formed between
a) A and B
b) C and D
c) A and D
[3]