laboursonline – MCQs, Mock Tests | Chemistry Chemistry MCQ Question

The element cesium bears resemblance with

1. Ca
2. Cr
3. Both of the above
4. None of the above

✅ Correct Answer: 4

The ore CaSO4.H2O has the general name

1. Gypsum
2. Dolomite
3. Calcite
4. Plaster of Paris

✅ Correct Answer: 1

Downs cell is used to prepare

1. Sodium carbonate
2. Sodium bicarbonate
3. Sodium metal
4. Sodium hydroxide

✅ Correct Answer: 3

Which element is produced at the cathode during the electrolysis of brine in Nelsons cell?

1. H2
2. Na
3. C?2
4. O2

✅ Correct Answer: 1

Ammonia may be prepared by heating ammonium chloride with

1. Water
2. NaCl
3. Aqueous sodium hydroxide
4. H2SO4

✅ Correct Answer: 3

Calcium carbide is prepared by heating lime with coke at

1. 2500?C
2. 2600?C
3. 2700?C
4. 2800?C

✅ Correct Answer: 4

Crystals of Na2CO3. 10H2O when exposed to air

1. Lose water and remain solid
2. Gain water and remain solid
3. Gain water and become liquid
4. Remains unchanged

✅ Correct Answer: 1

Which one of the following substances conducts electricity by the movement of ions?

1. Graphite
2. Copper
3. Molten sodium chloride
4. Mercury

✅ Correct Answer: 3

Which one of the following gives white precipitate with aqueous solution of BaC?2?

1. NaHCO3
2. NaNO3
3. Na2CO3
4. Na2CrO4

✅ Correct Answer: 3

Which one of the following carbonate is water insoluble?

1. Na2CO3
2. K2CO3
3. (NH4)2CO3
4. CaCO3

✅ Correct Answer: 4

The deliquescence is a property in which a solid

1. Absorbs moisture and remains solid
2. Absorbs moisture and turns to liquid form
3. Loses water of crystallization
4. Increases the number of water of crystallization

✅ Correct Answer: 2

In diaphragm cell hydrogen is discharged by the reduction of

1. Water
2. HCI
3. Na+
4. NaCl

✅ Correct Answer: 1

In diaphragm cell level of brine in anode compartment is kept slightly higher which prevents

1. Hydroxide ions to reach anode
2. Chlorine gas to mix
3. Cathode to decay
4. All of the above

✅ Correct Answer: 1

Gypsum is applied to the soil as a source of

1. Ca and P
2. S and P
3. Ca and S
4. we could not apply

✅ Correct Answer: 3

Alkali and alkaline earth metals impart colours when heated over burner. It is due to

1. Smaller electronegativity of alkali metals
2. Smaller ionic radius of these metals
3. Excitation of Excitation of electrons from low energy levels to higher energy levels
4. Excitation of electrons from low energy levels to higher energy levels

✅ Correct Answer: 3

Which one of the following alkali metals forms only normal oxide when it reacts with O2?

1. Lithium
2. Sodium
3. Potassium
4. Rubidium

✅ Correct Answer: 1

First ionization potential of alkaline earth metal is greater than alkali metals because

1. They are more reactive
2. They have greater atomic radii
3. They have smaller atomic sizes
4. All

✅ Correct Answer: 3

Which one of the following pairs shown diagonal relationship in the periodic table?

1. Sodium and Lithium
2. Lithium and magnesium
3. Lithium and beryllium
4. Boron and Beryllium

✅ Correct Answer: 2

NaOH is named as caustic soda because

1. It corrodes the organic tissues
2. It is used in soda water
3. It reacts with chlorine gas
4. It reacts with fats to form soap

✅ Correct Answer: 1

Sodium is not observed in +2 oxidation state because of its

1. high first ionization potential
2. high second ioniation potential
3. high ionic radius
4. high electronegativity

✅ Correct Answer: 2

Carnalite has chemical formula

1. KCI
2. KCI.MgCl2.6H2O
3. Na2B4O7.10H2O
4. CaCO3.MgCO3

✅ Correct Answer: 2

Magnesium metal does not burn in the vessel containing

1. N2
2. O2
3. N2 and O2
4. Ne

✅ Correct Answer: 4

Electrolysis of dilute solution of NaCl results at the anode

1. sodium
2. hydrogen
3. chlorine
4. oxygen

✅ Correct Answer: 4

Second ionization potential of alkali metals are very high due to

1. being s-block elements
2. inert gas configurations
3. ns1 electronic configuration
4. being metals

✅ Correct Answer: 2

Which ion will have maximum value of heat of hydration?

1. A1+3
2. Cs+
3. Ba+
4. Mg+2

✅ Correct Answer: 1

Which one can form complex?

1. Na
2. Cr
3. Li
4. K

✅ Correct Answer: 3

Which one is natron?

1. Na2CO3
2. Na2CO3.10H2O
3. Na2CO3.H2O
4. NaHCO3

✅ Correct Answer: 3

Addition of 2% gypsum in cement

1. Triggers hydration
2. Triggers hydrolysis
3. Prevents rapid hardening
4. all of the above

✅ Correct Answer: 3

Which one is least ionic in nature and decompose on heating.

1. LiOH
2. NaOH
3. KOH
4. CsOH

✅ Correct Answer: 1

Among the halogens the rare element is

1. Fluorine
2. Chlorine
3. Astatine
4. Iodine

✅ Correct Answer: 3

The colour of chlorine gas is

1. pale yellow
2. freenish yellow
3. reddish brown
4. grayish black

✅ Correct Answer: 2

Vander Waals forces are stronger in

1. F2
2. Cl2
3. Br2
4. I2

✅ Correct Answer: 4

The most powerful oxidizing agent among the halogens is

1. F2
2. Cl2
3. Br2
4. I2

✅ Correct Answer: 1

Which of the following statements is incorrect about fluorine

1. fluorine is restricted to -1 oxidation state
2. fluorine follows octet rule and as well as extended octet rule
3. fluorine has lowest dissociation energy among the halogens
4. both b and c

✅ Correct Answer: 4

The halogen which reacts spontaneously with gold (Au) to form Au+3 is

1. F2
2. Cl2
3. Br2
4. I2

✅ Correct Answer: 2

Which one of the following is the weakest acid in water

1. HF
2. HCI
3. HBr
4. HI

✅ Correct Answer: 1

The halogen which reacts very slowly with halogen is

1. Fluorine
2. Chlorine
3. Bromine
4. Iodine

✅ Correct Answer: 4

Which of the following represents the correct electronic configuration of VII A group elements in the ground state?

1. ns2p2
2. ns2p4
3. ns2p5
4. ns2p6

✅ Correct Answer: 3

The halogen having highest electron affinity is

1. Fluorine
2. Chlorine
3. Bromine
4. Iodine

✅ Correct Answer: 2

Which is the strongest acid?

1. HCIO
2. HCIO2
3. HCIO3
4. HCIO4

✅ Correct Answer: 4

Bromine can be liberated from KBr solution by the action of

1. Iodine solution
2. Chlorine
3. NaCl
4. Ki

✅ Correct Answer: 2

Bleaching powder is an example of

1. Normal salt
2. Double salt
3. Mixed salt
4. Complex

✅ Correct Answer: 3

Consider the following reaction- 2KCIO3 + H2C2O4 + H2SO4 ? K2SO4 + 2H2O + 2CO2 + Oxide Which oxide of chlorine is produced in the above reaction?

1. Cl2O
2. ClO2
3. Cl2O6
4. Cl2O7

✅ Correct Answer: 2

Which of the following oxides of iodine is used for quantitative analysis of CO?

1. I2O4
2. I4O2
3. I2O5
4. All are equally useful

✅ Correct Answer: 3

Consider the following reaction- 3Cl2 + 6NaOH ? NaClO3 + 5NaCl + 3H2O This reaction is

1. Displacement reaction
2. Double displacement reaction
3. Disproportionation reaction
4. Reduction reaction

✅ Correct Answer: 3

Which of the halogen has highest electronegativity?

1. Fluorine
2. Chlorine
3. Bromine
4. Iodine

✅ Correct Answer: 1

Which of the halogen can displace other three elements?

1. Flourine
2. Chlorine
3. Iodine
4. Bromine

✅ Correct Answer: 1

Which of the following statements is incorrect about halogens?

1. All are non-metals
2. All the halogens have electronic conviguration ns2p5
3. They have high electron attinity and ionization energy
4. All the halogens react with noble gases to form their halides

✅ Correct Answer: 4

The chemical formula of sodium hypochlorite is

1. NaCLO
2. NaClO2
3. NaClO3
4. NaClO4

✅ Correct Answer: 1

Fluorine can react with

1. Xe
2. Kr
3. Rn
4. All of the above

✅ Correct Answer: 4

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