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Mixed Test (Chemistry)

Description: Engineering entrance
Number of Questions: 15
Created by:
Tags: Engineering entrance Oxidation Number Redox Reactions in Aqueous Solution Electrochemical Redox reactions Group 16 Elements Group 17 Elements D and F-Block Elements d- and f- Block Elements
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Aniline reacts with acetic anhydride to form acetanilide. This reaction is known as ____________.

  1. Schotten Baumann reaction

  2. Ullmann reaction

  3. Gomberg reaction

  4. Sandmeyer reaction

  5. None of these

Show answer
Correct Option: A
Explanation:

This option is correct because in acid chloride or acid anhydride, the H-atom of amino group is acylated, i.e. replaced by acyl group. This reaction is called Schotten Baumann reaction. 

The chemical reagent used for leaching of gold and silver ores is

  1. sodium hydroxide

  2. potassium cyanide

  3. sodium thiosulphate

  4. sodium bicarbonate

  5. none of these

Show answer
Correct Option: B
Explanation:

This option is correct because the leaching of gold means gold cyanidation of gold and for silver ores cyanidation of silver. Potassium cyanide (KCN) is used for extraction of gold and silver with respect to water to form soluble coordination complexes (K[Ag(CN)2], K[Au(CN)2]).

The reaction of aqueous potassium permanganate with hydrogen peroxide in acidic condition gives

  1. Mn+4 and O2

  2. Mn+2 and O2

  3. Mn+3 and O3

  4. Mn+3 and MnO4

  5. None of these

Show answer
Correct Option: B
Explanation:

This option is correct because when the reaction of potassium permanganate ions and hydrogen peroxide in acidic medium takes place,  Mn+2 and O2 are evolved.

By which of the following reactions can gold sol be prepared?

  1. Hydrolysis of gold(III) chloride

  2. Oxidation of gold by aqua regia

  3. By peptization

  4. Reduction of gold (III) chloride formalin solution

  5. None of these

Show answer
Correct Option: D
Explanation:

This option is correct because gold chloride reacts with formaldehyde and water to give gold sol and formic acid.

The yellow litharge is prepared by _________.

  1. massicoto

  2. red lead

  3. mosaic gold

  4. only 1 and 2

  5. none of these

Show answer
Correct Option: A
Explanation:

This option is correct because on heating of lead with galena in air at 3000C, yellow litharge is formed.

Which of the following statements is not correct about the interhalogen properties?

  1. They are all covalent compound.

  2. They are volatile solid or liquid except ClF.

  3. IF5 has square pyramidal structure.

  4. They are paramagnetic in nature.

  5. None of these

Show answer
Correct Option: D
Explanation:

This is correct answer because all interhalogen compound sare mostly diamagnetic in nature.

The number of electrons that are involved in the reduction of permanganate to manganese (II) salt, manganate and manganese dioxide respectively are __________.

  1. 5, 1 and 3

  2. 5, 3 and 1

  3. 2, 7 and 1

  4. 2, 3 and 1

  5. None of these

Show answer
Correct Option: A
Explanation:

This option is correct  because in reduction of permanganate ion to manganese (II) salt, 5 electrons are involved,  In case of the manganate ions, 3 electrons are involved and in manganese oxide, only 1 electron is involved.

Which of the following species is/are isoelectronic? (1) NH3

(2) CH3+

(3) NH2-

(4) NH4+

  1. Only (1), (2) and (3)

  2. Only (2), (3) and (4)

  3. Only (1), (2) and (4)

  4. Only (1), (3) and (4)

  5. None of these

Show answer
Correct Option: D
Explanation:

This option is correct because 1, 3 and 4 species are isoelectronic having 10 electrons.

Which of the following is the chemical formula of butter tin?

  1. SnCl4.5H2O

  2. SnCl6(NH4)2

  3. SnS2

  4. SnO2

  5. None of these

Show answer
Correct Option: A
Explanation:

This option is correct because the Stannic Chloride Pentahydrate is used for mordant in dyeing under the name oxymuriate of tin or butter tin.

In acidic medium, hydrogen peroxide changes Cr2O72- to CrO5, which has two (-O-O-) bonds. The oxidation state in CrO5 is

  1. +1

  2. +3

  3. +6

  4. -5

  5. None of these

Show answer
Correct Option: C
Explanation:

This option is correct because CrO5 has butterfly structure having two peroxo bonds. Peroxo has -1 oxidation state. CrO5 x + 4(-1) + 1(-2) = 0, x = +6

When the plaster of Paris is heated above 2000C, it is converted into ____________.

  1. dead burnt

  2. epsom salt

  3. milk of magnesia

  4. hydrolith

  5. none of these

Show answer
Correct Option: A
Explanation:

This option is correct because when plaster of Paris is heated above 2000C, it loses the water molecules and is converted in to anhydrous salts, called dead burnt.

Magnesia alba is obtained by the addition of ____________.

  1. MgCO3 and MgSO4.7H2O

  2. CaCO3 and H2O

  3. AgCl and HNO3

  4. MgCl2 and MgO

  5. None of these

Show answer
Correct Option: A
Explanation:

This option is correct. Magnesia alba is a white substance, which is used in medicine as an antacid laxative and tooth powder, which is formulated as [Mg(CO3)x.Mg(OH)2]y.ZH2O. 

Potassium dichromate belongs to ____________ crystal system.

  1. tetrahedral

  2. orthorhombic

  3. triclinic

  4. only 1 and 2

  5. none of these

Show answer
Correct Option: C
Explanation:

This option is correct because it is formed by unequal length; 7 crystal systems, three basis vectors and it has one peroxo bond.

Which of the following statements is incorrect?

  1. Ozone oxidises lead sulphide to lead sulphate.

  2. Ozone oxidises nitric oxide to nitrogen dioxide.

  3. Two oxygen-oxygen bond length in ozone are different.

  4. Options 1 and 2 correct

  5. None of these

Show answer
Correct Option: C
Explanation:

This option is correct because the two O-O atom of the bond length in ozone molecule are same, i.e. 1.278A0 and their bond angle is 116.80.

Permanent hardness of water can be removed by _____________.

  1. sodium sulphate

  2. sodium bicarbonate

  3. washing soda

  4. sodium chloride

  5. none of these

Show answer
Correct Option: C
Explanation:

This option is correct because washing soda removes the permanent hardness by converting soluble calcium and magnesium compound into insoluble carbonates.

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