Chemistry Science Paper 2 2014-2015 (English Medium) ICSE Class 10 Question Paper Solution

Select from the list the gas that matches the description given in case

[ammonia, ethane, hydrogen chloride, hydrogen sulfide, ethyne]

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

Select from the list the gas that matches the description given in case

[ammonia, ethane, hydrogen chloride, hydrogen sulfide, ethyne]

This gas produces dense white fumes with ammonia gas.

Select from the list the gas that matches the description given in case

[ammonia, ethane, hydrogen chloride, hydrogen sulphide, ethyne]

This gas is used for welding purposes.

Select from the list the gas that matches the description given in case

[ammonia, ethane, hydrogen chloride, hydrogen sulfide, ethyne]

This gas is also a saturated hydrocarbon

Select from the list the gas that matches the description given in case

[ammonia, ethane, hydrogen chloride, hydrogen sulfide, ethyne]

This gas has a characteristic rotten egg smell.

Choose the most appropriate answer of the following:

Among the elements given below, the element with the least electronegativity is:

(A) Lithium

(B) Carbon

(C) Boron

(D) Fluorine

Choose the most appropriate answer of the following:

Identify the statement which does not describe the property of alkenes:

(A) They are unsaturated hydrocarbons

(B) They decolorize bromine water

(C) They can undergo addition as well as substitution reactions

(D) They undergo combustion with oxygen forming carbon dioxide and water.

Choose the most appropriate answer of the following:

This is not an alloy of copper:

(A) Brass

(B) Bronze

(C) Solder

(D) Duralumin.

Choose the most appropriate answer of the following:

Bonding in this molecule can be understood to involve coordinate bonding

(A) Carbon tetrachloride

(B) Hydrogen

(C) Hydrogen chloride

(D) Ammonium chloride

Choose the most appropriate answer of the following:

Which of the following would weigh the least?

(A) 2-gram atoms of Nitrogen.

(B) 1mole of Silver

(C) 22.4 liters of oxygen gas at 1 atmospheric pressure and 273K

(D) 6.02 x 10²³ atoms of carbon.

[Atomic masses: Ag=108, N=14, O=16, C=12]

Calculate the mass of Calcium that will contain the same number of the atom as are present in 3.2 gm of Sulphur.

[Atomic masses: S=32, Ca=40]

If 6 liters of hydrogen and 4 liters of chlorine are mixed and exploded and if water is added to the gases formed, find the volume of the residual gas.

If the empirical formula of a compound is CH and it has a vapor density of 13, find the molecular formula of the compound.

State one relevant observation for the following:

When crystals of copper nitrate are heated in a test tube.

State one relevant observation for the following

When the gaseous product obtained by dehydration of ethyl alcohol is passed through bromine water.

State one relevant observation for the following

When hydrogen sulfide gas is passed through lead acetate solution.

State one relevant observation for the following

When ammonia gas is burnt in an atmosphere of excess oxygen.

State one relevant observation for the following:

At the anode when aqueous copper sulphate solution is electrolysed using copper electrodes.

The acid which is used in the preparation of a volatile acid

Identify the acid in the following case:

The acid which produces sugar charcoal from sugar.

The acid which is prepared by catalytic oxidation of ammonia.

Identify the acid in the following case:

The acid on mixing with lead nitrate solution produces a white precipitate, which is insoluble even on heating.

The acid on mixing with silver nitrate solution produces a white precipitate which is soluble in excess ammonium hydroxide

Give appropriate scientific reasons for Zinc oxide can be reduced to zinc metal by using
carbon, but aluminium oxide cannot be reduced by a reducing agent

Give appropriate scientific reasons for Carbon tetrachloride does not conduct electricity.

Give appropriate scientific reasons for During electrolysis of molten lead bromide, graphite anode is preferred to other electrodes.

Give appropriate scientific reasons for The electrical conductivity of acetic acid is less in comparison to the electrical conductivity of dilute sulphuric acid at a given concentration.

Give appropriate scientific reasons for Electrolysis is of molten lead bromide is considered to be a redox reaction.

Give balanced chemical equations for the following conversions A, B, and C:

Differentiate between the terms strong electrolyte and weak electrolyte. (stating any two differences)

Explain the bonding in methane molecule using electron dot structure.

The metal of Group 2 from top to bottom arc Be, Mg, Ca, Sr, and Ba.

1) Which one of these elements will form ions most readily and why?

2) State the common feature in the electronic configuration of all these elements.

Arrange the following as per the instruction given in the bracket.

Cs, Na, Li, K, Rb (increasing order of metallic character).

Arrange the following as per the instruction given in the bracket:

Mg, Cl, Na, S, Si (decreasing order of atomic size).

Arrange the following as per the instructions given in the brackets:

Na, K, Cl, S, Si (increasing order ionization energy)

Arrange the following as per the instructions given in the brackets:

Cl, F, Br, I (increasing order of electron affinity)

Choose the most appropriate answer from the following list of oxides which fit the description.

[SO₂, SiO₂, Al₂O₃, MgO, CO, Na₂O]

A basic oxide.

Choose the most appropriate answer from the following list of oxides which fit the description

[SO₂, SiO₂, Al₂O₃, MgO, CO, Na₂O]

An oxide which dissolves in water forming an acid

Choose the most appropriate answer from the following list of oxides which fit the description

[SO₂, SiO₂, Al₂O₃, MgO, CO, Na₂O]

An amphoteric oxide

Choose the most appropriate answer from the following list of oxides which fit the description.

A covalent oxide of a metalloid.

SO₂

SiO₂

Al₂O₃

MgO

CO

Na₂O

Element X is a metal with a valency 2, Y is 3 non- metal with a valency 3.

1) Write an equation to show how Y from an ion.

2) If Y is a diatomic gas, write an equation for the direct combination of X and Y to form a compound.

Give a balanced chemical equation for the ethanoic acid to ethyl ethanoate.

Give balanced chemical equations for Calcium carbide to ethyne.

Give balanced chemical equations for Sodium ethanoate to methane.

Using their structural formulae identify the functional group by circling them

Dimethyl ether

Using their structural formulae identify the functional group by circling them

Propanone.

Name the following:

The process by which ethane is obtained from ethane.

Name the following:

A hydrocarbon which contributes towards the greenhouse effect.

Name the following:

The distinctive reaction that takes place when ethanol is treated with acetic acid.

Name the following:

The property of element by virtue of which atoms of the element can link to each other in the form of a long chain or ring structure.

Name the following:

Reaction when an alkyl halide is treated with alcoholic potassium hydroxide.

Identify the anion present in the following compounds:

A salt M on treatment with concentrated sulphuric acid produces a gas which fumes in moist air and gives dense fumes with ammonia

Identify the anion present in the following compounds:

A salt D on treatment with dilute sulphuric acid produces a gas which turns lime water milky but has no effect on acidified potassium dichromate solution

Identify the anion present in the following compounds:
When barium chloride solution is added to salt solution E a white precipitate insoluble in dilute hydrochloric acid is obtained.

The following table shows the test a student performed on four different aqueous solutions which are X, Y, Z and W. Based on the observations provided, identify the cation present:

Give balanced chemical equations for Lab preparation of ammonia using an ammonium salt

Give balanced chemical equations for Reaction of ammonia with excess chlorine.

Give balanced chemical equations for Reaction of ammonia with sulphuric acid.

Consider the following reaction and based on the reaction answer the questions that follow:

Calculate:

1) the quantity in moles of (NH₄)₂Cr₂O₇ if 63gm of(NH₄)₂Cr₂O₇ is heated.

2) the quantity in moles of nitrogen formed.

3) the volume in liters or dm3 of N2 evolved at S.T.P.

4) the mass in grams of Cr2O3 formed at the same time

(Atomic masses: H=1, Cr= 52, N=14]

For the substance given below, describe the role played in the extraction of aluminium.

Cryolite

For the substance given below, describe the role played in the extraction of aluminium.

Sodium hydroxide

For the substance given below, describe the role played in the extraction of aluminium.

Graphite

Explain why In the electrolysis of alumina using the Hall Heroult's Process the electrolyte is covered with powdered coke

Explain why Iron sheets are coated with zinc during galvanization.

Give balanced chemical equations for the action of sulphuric acid on the following:

Potassium hydrogen carbonate.

Give balanced chemical equations for the action of sulphuric acid on the following:

Sulphur

In the contact process for the manufacture of sulphuric acid give the equations for the conversion of sulphur trioxide to sulphuric acid.

Copy and complete the following table:

Write the equation taking place at the anode

 Explain the following:

Dilute nitric acid is generally considered a typical acid but not so in its reaction with metals.

Explain the following:

Concentrated nitric add appears yellow when it is left standing in a glass bottle.

Explain the following:

An all-glass apparatus is used in the laboratory preparation of nitric acid.

The following are pertaining to the laboratory preparation of hydrogen chloride gas.

Write the equation for its preparation mentioning the condition required.

The following are pertaining to the laboratory preparation of hydrogen chloride gas.

Name the drying agent used and justify your choice.

The following are pertaining to the laboratory preparation of hydrogen chloride gas.

State a safety precaution you would take during the preparation of hydrochloric acid.

An element L consists of molecules.

What type of bonding is present in the particles that make up L?

An element L consists of molecules.

When L is heated with iron metal, it forms a compound FeL. What chemical term would you use to describe the change undergone by L?

From the list of the following salts choose the salt that most appropriately fits the description is given in the following:

[AgCl, MgCl₂, NaHSO₄, PbCO₃, ZnCO₃, KNO₃, Ca(NO₃)₂]

A deliquescent salt

From the list of the following salts choose the salt that most appropriately fits the description is given in the following:

[AgCl, MgCl₂, NaHSO₄, PbCO₃, ZnCO₃, KNO₃, Ca(NO₃)₂]

An insoluble chloride.

From the list of the following salts choose the salt that most appropriately fits the
description is given in the following:

[AgCl, MgCl₂, NaHSO₄, PbCO₃, ZnCO₃, KNO₃, Ca(NO₃)₂]

On heating, this salt gives a yellow residue when hot and white when cold

From the list of the following salts choose the salt that most appropriately fits the
description is given in the following:

[AgCl, MgCl₂, NaHSO₄, PbCO₃, ZnCO₃, KNO₃, Ca(NO₃)₂]

On heating this salt, a brown colored gas is evolved.