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Chemistry (Engineering Entrance)

Description: this test contains question on chemistry for AIEEE including questions from various topics as per the latest trend of competitive examinations
Number of Questions: 30
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Tags: chemistry Colligative Properties Colligative Properties and Determination of Molar Mass Imperfections in Solids Carboxylic Acids Preparation of Carboxylic Acids Le-Chateliers Principle Law of Chemical Equilibrium and Equilibrium Constant Enthalpy Change in Chemical Reactions Enthalpy Changes During Phase Transformations
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If an oxide having metal deficiency defect is heated in di-oxygen, then its conductivity

  1. increases

  2. decreases

  3. remains constant

  4. can not be determined


Correct Option: A
Explanation:

When oxygen oxidizes some of the metal ions and this increases the number of positive centres, hence the conductivity increases.

When a solution of sugar is slowly frozen, the first solid which separates is

  1. ice

  2. solid solution of sugar and ice

  3. sugar

  4. none of these


Correct Option: A
Explanation:

When sugar is added to water and a mixture of these two is formed, it suffers from lowering in freezing point and the freezing point of water is lowered and hence the first solid which separates out is ice. It is one of the colligative properties of a solution which is subjected to a change by the addition of solute.

Which one of the following reactions is favourable at low pressure?

  1. H2 + I2 ⇌ 2HI

  2. PCl5 ⇌ PCl3 + Cl2

  3. N2 + 2H2 ⇌ 2NH3

  4. N2 + O2 ⇌ 2NO


Correct Option: B
Explanation:

  We know that low pressure favours the reaction accompanied with increase in number of moles and in the given option, the number of moles of reactants are less than number of moles of product or we can say there is an increase in number of moles in product side, so this reaction will be favoured at low pressure.

Arrange the following oxy-acids in correct order in terms of increasing acidic strength.

  1. HClO > HClO2 > HClO3 > HClO4

  2. HClO4 > HClO3 > HClO2 > HClO

  3. HClO > HClO2 > HClO4 > HClO3

  4. HClO3 > HClO4 > HClO2 > HClO


Correct Option: B
Explanation:

  We know that acidic strength increases with increase in oxidation number.Here we have oxidation number of chlorine as follows:

HClO = +1, HClO2 = +3, HClO3 = +5, HClO4 = +7. 

In the given option the order given is correct.

Fusion bomb involves

  1. combination of lighter nuclei into bigger nucleus

  2. destruction and bigger nucleus is divided into smaller nuclei

  3. combustion of oxygen

  4. none of these


Correct Option: A
Explanation:

Fusion bomb involves the principle pf nuclear fusion according to which when two lighter nuclei combine to form a bigger nucleius, then it is characterised by emission or liberation of tremendous amount of energy.

Which of the following statements is correct?

  1. The magnitude of second electron affinity of sulphur is greater than that of oxygen.

  2. The magnitude of second electron affinity of sulphur is less than that of oxygen.

  3. First electron affinity of bromine and iodine are approximately the same.

  4. None of these


Correct Option: B
Explanation:

The electronic configuration of sulphur is 1s22s22p63s23p4 and oxygen is  1s22s22p4 , in terms of shell configuration it can be represented as follows: S=2,8,6 and O=2,6. Since the valence shell is having deficiency of two electrons and hence possesses, high electron affinity. Now when sulphur and oxygen both will accept one electron then their electronic shell configuration will become S = 2,8,7 and O = 2,7. Now it is easy for sulphur to accept one more electron as compared to oxygen because it is having three shells and hence the nuclear attraction in valence shell will be less as compared to oxygen having only two shells, hence the second electron affinity of sulphur will be less than that of oxygen.

Which of the following is not true regarding chemisorption?

  1. It is reversible in nature.

  2. Heat of adsorption is of order 20 to 400 KJ mol-1.

  3. It forms unimolecular layer.

  4. It is specific in nature.


Correct Option: A
Explanation:

Chemisorption is irreversible in nature as it involves chemical changes and we know that chemical changes are irreversible.

The oxidation state of sulphur in the cyclic trimer of sulphur trioxide is

  1. +1

  2. +3

  3. +2

  4. +6


Correct Option: D
Explanation:

  Cyclic trimer of sulphur trioxide is (SO3)3 , the oxidation of sulphur in it can be calculated as follows:

Let the oxidation state of sulphur be x,hence 3x + 18 = 0, so x = 18/3 = +6

The ionic radii of N3-, O2-, F-, Na+ follows the order

  1. N3- > O2- > F- > Na+

  2. N3- > Na+ > O2- > F-

  3. Na+ > O2- > N3- > F-

  4. O2- > F- > Na+ > N3-


Correct Option: A
Explanation:

Since all the species given in the option are isoelectronic and we know that for isoelectronic species, the ionic radii increases with decrease in nuclear charge and in the given  question the order of decrease of nuclear charge is  N3- > O2- > F- > Na+ which is the same as given in the option .

Arsenic sulphide is a negative sol. The reagent with the least precipitating power is

  1. AlCl3

  2. NaCl

  3. CaF2

  4. Glucose


Correct Option: D
Explanation:

Glucose is a covalent compound, hence it cannot give ions in solution and hence will be possessing the least precipitating power.

In which of the following cases friedal craft reaction is not possible?

  1. C6H5OH

  2. C6H5NH2

  3. C6H5NO2

  4. C6H5CH3


Correct Option: C
Explanation:

In C6H5NO2, the electron withdrawing group -NO2 deactivates the benzene ring to the extent that it cannot respond to Friedel Craft reaction. Hence, this option is correct.

Study the following reaction carefully and choose the correct answer based on the same.

In the chemical reaction: Ag2O + H2O + 2e- -----> 2Ag + 2OH-

  1. silver is oxidised

  2. silver is reduced

  3. hydrogen is reduced

  4. none of these


Correct Option: B
Explanation:

 In the given reaction on reactants side, silver is having an oxidation state of +1 in Ag2O and in product side it is having oxidation state of 0 in Ag. Hence, it suffers a change in oxidation state from +1 to 0 which is actually a decrease in oxidation state , hence silver is reduced.

Statement 1: Alkali metal ions are very easily reduced. Statement 2: Alkali metals have very low value of ionisation energies.

Read the above statements carefully and choose the correct answer.

  1. Statement 1 is correct. Statement 2 is correct and Statement 2 is correct explanation of Statement 1.

  2. Statement 1 is correct. Statement 2 is correct and Statement 2 is not the correct explanation of Statement 1.

  3. Statement 1 is correct. Statement 2 is incorrect.

  4. Statement 1 is incorrect, statement 2 is correct.


Correct Option: D
Explanation:

In this option statement 1 is said to be incorrect which is true as alkali metals get easily oxidized and not reduced by donating electrons from outermost shell and statement 2 is said to be correct which is true as alkali metals possess low value of ionization enthalpy.

The process of dissolution of salt is exothermic if

  1. lattice energy = hydration energy

  2. lattice energy < hydration energy

  3. lattice energy > hydration energy

  4. none of these


Correct Option: B
Explanation:

 If the lattice energy is less than the hydration energy,  more heat is needed to be supplied in order to dissolve the salt in the solution.Hence it will be exothermic.

Study the following statements carefully and choose the correct answer based on them.

Statement 1: The charge to mass ratio of the particles in anode rays depends on nature of gas taken in discharge tube. Statement 2: The particles in anode rays carry positive charge.

  1. Statement 1 is correct. Statement 2 is correct and Statement 2 is correct explanation of Statement 1.

  2. Statement 1 is correct. Statement 2 is correct and Statement 2 is not the correct explanation of Statement 1.

  3. Statement 1 is correct, statement 2 is incorrect.

  4. Statement 1 is incorrect, statement 2 is correct.


Correct Option: B
Explanation:

Statement 1 is correct as charge to mass ratio of the particles of anode rays depends upon the nature of the gas as it is not emitted from anode , statement 2 is also correct that anode rays particles consist of positive ions , and statement 2 is not the explanation of statement 1.

Which of the following is not an assumption of kinetic theory of gases?

  1. The actual volume of the gaseous molecules is negligible as compared to the total volume of the gas.

  2. The critical temperature is the measure of the kinetic energy of the molecule.

  3. The effect of gravity on motion of molecules is negligible.

  4. None of these


Correct Option: B
Explanation:

Given statement regarding the Kinetic Theory of gases is incorrect because it is not the critical temperature but only temperature which is the measure of the kinetic energy of the molecules. 

Which of the following is used as barium metal for getting X-ray spectrum of the human digestive system?

  1. BaSO4

  2. BaCl2

  3. BaF2

  4. BaCO3


Correct Option: A
Explanation:

Barium sulphate is water soluble and opaque to X-rays,  hence it can be used as barium metal for getting  X-ray spectrum of the human digestive system.

Statement 1: O2 molecules are paramagnetic in nature. Statement 2: O2 molecules contain two unpaired electrons in anti-bonding orbitals. Study the above statements carefully and choose the correct option based on these.

  1. Statement 1 is correct. Statement 2 is correct and statement 2 is correct explanation of statement 1.

  2. Statement 1 is correct. Statement 2 is correct and statement 2 is not the correct explanation of statement 1.

  3. Statement 1 is correct. Statement 2 is incorrect.

  4. Statement 1 is incorrect, statement 2 is correct.


Correct Option: A
Explanation:

We know that as per the molecular orbital theory,O2 contains two electrons in the anti-bonding orbital if we have a look on the molecular orbital diagram of O2 and hence, it is paramagnetic in nature. Also statement 2 is correct that O2 contains two unpaired electrons in anti bonding orbital, and statement 2 is correct explanation of statement 1 as discussed above. 

In cubic closed pack structure of mixed oxides, the lattice is made up of oxide ions, one eighth of the octahedral voids are occupied by divalent ions (A2+), while one half of the octahedral voids are occupied by trivalent ions (B3+). The formula for the oxide is

  1. A3B2O4

  2. A2B2O4

  3. AB2O4

  4. None of these


Correct Option: C
Explanation:

  Let the number of oxides be = x

So number of octahedral  voids = x

And number of tetrahedral voids = 2x

Number of A2+ ion = 2x/8 = x/4

Number of B3+ ions = x/2

A2+ : B3+ : O2-

x/4: x/2: x

1:2:4 

Hence the formula for the oxide is AB2O4

For a monoamino dicarboxylic acid, the isoelectric point is

  1. greater than 7

  2. lesser than 7

  3. equal to 7

  4. none of these


Correct Option: B
Explanation:

Monoamino dicarboxylic acids, have one extra -COOH and hence more base is required to neutralize. Therefore, pH will be lower than 7.

Which of the following polymers consists of extensive cross linking?

  1. Thermosetting polymers

  2. Elastomers

  3. Fibres

  4. Thermoplastics


Correct Option: A
Explanation:

 It is the extensive cross-linking of the thermosetting polymer that it becomes infusible on heating.

In which case, the wavelength emitted is minimum?

  1. An electron jumps from 2nd to 1st level

  2. An electron jumps from 3rd to 2nd level

  3. An electron jumps from 4th to 3rd level

  4. An electron jumps from 5th to 4th level


Correct Option: A
Explanation:

  Applying the Rydberg's equation 1/λ = R0[1/n12 - 1/n22] . 

We get 1/λ = R0 [3/4] or λ = 1.33/R0. This value of wavelength is the least among the given options.

Point out the incorrect statement regarding the liquid junction potential.

  1. LJP is an additional source of potential difference across the interface of two electrolytes

  2. LJP arises due to differing ionic mobility in two different liquids

  3. LJP is an essential part of electrolyte concentration cell

  4. Salt bridge promotes liquid junction potential


Correct Option: D
Explanation:

Given statement regarding the liquid junction potential is incorrect as salt bridge is used to reduce the liquid junction potential.

Which of the following is known as Pseudo Alum?

  1. KMn(SO4)2. 12H2O

  2. KCr(SO4)2. 12H2O

  3. NH4Fe(SO4)2. 12H2O

  4. FeSO4.Al2(SO4)3. 24H2O


Correct Option: D
Explanation:

  Pseudo alum has the general formula MIISO4. M2III (SO4)3. 24H2O. 

So on  comparing we get FeSO4.Al2(SO4)3.24H2O is pseudo alum.

Directions: The following question has four choices out of which ONLY ONE is correct.

Which of the following functional compounds do not give Schotten-Baumann reaction?

  1. Alcohols

  2. Phenols

  3. Amines

  4. Ether


Correct Option: D
Explanation:

Schotten-Baumann reaction is the acyclation of alcohols, phenols and amines, and not ethers, by shaking with aromatic acyl chloride in the presence of a base, usually aqueous sodium hydroxide. Hence, this test is not given by ethers.

Plumbo-solvency is represented by the reaction

  1. 2Pb + O2 → 2PbO

  2. Pb + 2HCl → PbCl2 + H2

  3. 2Pb + O2 + 2H2O → 2Pb(OH)2

  4. 2PbS + 3O2 → 2PbO + 2SO2


Correct Option: C
Explanation:

 Plumbo-solvency is said to take place when Pb gets converted to its hydroxide on reaction with water in presence of oxygen,  the given option satisfies all the conditions. 

In the reaction aA + bB +cC → products, following observations are made. I - if concentration of A is doubled, keeping the concentration of B and C constant, the rate of reaction becomes double.

II - if the concentration of B is halved, keeping the concentration of A and C constant the rate of reaction remains unaffected.

III - If concentration of C is made 1.5 times, the rate of reaction becomes 2.25 times.

The order of reaction is

  1. 1

  2. 2.5

  3. 3

  4. 3.5


Correct Option: C
Explanation:

The answer can be calculated as follows:

From observation 1, we observe that reaction is 1st order with respect to A.

From observation 2, we observe,that reaction is zero order with respect to B.

From observation 3, we observe that reaction is 2nd order with respect to C.

Hence in total the reaction is of 3rd order.

The reaction of RCH2CH2COOH with red phosphorus in presence of bromine to give R-CH2-CHBr-COOH is called

  1. Reimer Tiemann reaction

  2. Cannizaro reaction

  3. Sandmeyer's reaction

  4. Hell-Volhard Zelinsky reaction


Correct Option: D
Explanation:

Alpha halogenation of carboxylic acid in presence of red phosphorus is called Hell Volhard Zelinsky reaction.

For which of the following reactions ∆H is equal to ∆U?

  1. H2(g) + I2(g) → 2HI(g)

  2. H2(g) + 1/2O2(g) → H2O(l)

  3. 2SO3(g) → 2SO2(g) +O2(g)

  4. 2NO2(g) → N2O4(g)


Correct Option: A
Explanation:

The correct relation between ∆H and ∆U is given by the relation ∆H = ∆U +∆ngRT…………..where ∆ng is the difference in number of moles of gaseous products and reactants. For the given reaction ∆ng = (2-[1+1]) = 0, so ∆H = ∆U.

If M is molecular wt of the ion IO4-, what is the equivalent mass if it is converted into I2 in acidic medium?

  1. M/6

  2. M/7

  3. M/5

  4. M


Correct Option: B
Explanation:

For conversion of IO4- to I2 in acidic medium the reaction is as under.

IO4- + 7e- → I2……………… here oxidation state of I in IO4- is +7 and in I2 is 0, so gain in number of electrons is of +7. We know that equilibrium weight is given by

eqilibrium weight = molecular mass/gain in number of electrons

= M/7

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