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Chemistry (Class XI / XII)

Description: Chapterwise notes and Test Papers for Organic Chemistry, Chromatography, Inorganic Chemistry, Solution, Physics, Force, Work, Power, Energy, Osmosis, Chemistry, Rates of Reaction, Carbon, Compound, Chemical Reaction
Number of Questions: 25
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Tags: Organic Chemistry Chromatography Inorganic Chemistry Solution Physics Force Work Power Energy Osmosis Chemistry Rates of Reaction Carbon Compound Chemical Reaction Haloalkanes and Haloarenes Surface Energy and Surface Tension Viscosity (Poiseuille-s Equation Excluded) Viscosity Fluid Dynamics Mechanical Properties of Fluids Ideal Gas Law Ideal Gas Equation and Absolute Temperature
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What is the boiling point of chloroform?

  1. 336 K

  2. 334 K

  3. 331 K

  4. 330 K


Correct Option: B
Explanation:

The boiling point of chloroform is 334 K.

Plants take water from the earth's surface due to

  1. capillary action

  2. forward reaction

  3. ventricular action

  4. fast reaction


Correct Option: A
Explanation:

Capillary action is the process that plants use to pull water up from the ground. 

Rain drop is always spherical in shape because

  1. liquid tends to possess minimum surface tension area

  2. liquid tends to possess maximum surface tension area

  3. liquid tends to possess zero surface tension area

  4. None of these


Correct Option: A
Explanation:

The shape of a drop of rain is constrained by the surface tension, which tries to give it the shape for which the surface area is minimum. For a given volume, the spherical shape has the minimum surface area. That is why rain drops acquire spherical shape.

Surface tension of ethyl alcohol at 20oC is

  1. 24.9

  2. 22.3

  3. 30.3

  4. 35.6


Correct Option: B
Explanation:

Surface tension of ethyl alcohol at 20oC is 22.3. 

P, Poise is a unit of

  1. surface tension

  2. viscosity

  3. area

  4. force


Correct Option: B
Explanation:

Poise is a unit of viscosity.

Kinetic energy of molecule is directly proportional to

  1. temperature

  2. pressure

  3. volume

  4. density


Correct Option: A
Explanation:

The average kinetic energy of a collection of gas particles is directly proportional to absolute temperature only.

What will be the effect of increase in the temperature on viscosity of liquid?

  1. Decreases

  2. Increases

  3. Remains same

  4. Depends on other factors


Correct Option: A
Explanation:

The temperature dependence of liquid viscosity is the phenomenon by which liquid viscosity tends to decrease (or, alternatively, its fluidity tends to increase) as its temperature increases. 

Van der Waals' constant tells us about

  1. molecular attraction

  2. molecular repulsion

  3. Both 1 and 2

  4. None of these


Correct Option: A
Explanation:

The van der Waals constant 'a' reflects the strength of the attractive forces between the gas particles and the constant 'b' is a measure of the actual volume occupied by a mol of gas particles. 

The electrons which are present in the outer shell are

  1. valence electrons

  2. bond electrons

  3. excited electrons

  4. None of these


Correct Option: A
Explanation:

Valence electrons are electrons in one of the outer shells of an atom that can participate in forming chemical bonds with other atoms.

Which are the constituent particles in covalent crystal?

  1. Atoms

  2. Molecules

  3. Electrons

  4. Protons


Correct Option: A
Explanation:

The constituent particles in covalent crystal are atoms.

What is the value of 1 Poise?

  1. 0.1 Nsm-2

  2. 0.2 Ns-2

  3. 3 Ns

  4. None of these


Correct Option: A
Explanation:

1 pascal second is equal to 1 Ns/m2 or 10 poise. Thus, 1 poise = 0.1 Ns/m2

What is the melting point of Na?

  1. 270 K

  2. 371 K

  3. 389 K

  4. 474 K


Correct Option: B
Explanation:

The melting point of Na is 371 K. 

Molecular crystal is

  1. solid CO2

  2. CuSO4

  3. SiC

  4. None of these


Correct Option: A
Explanation:

A molecular solid is a solid composed of molecules held together by the van der Waals forces. Out of the given, only solid carbon dioxide is a molecular solid.

Stalagmometer is used to measure

  1. viscosity

  2. surface tension

  3. hyperteminas

  4. None of these


Correct Option: B
Explanation:

A stalagmometer is a device for investigating surface tension using the stalagmometric method. 

C6H6 is

  1. benzene

  2. methane

  3. ethane

  4. None of these


Correct Option: A
Explanation:

C6H6 is the molecular formula of benzene.

Which instrument is used to measure viscosity?

  1. Ostwald viscometer

  2. Stalagmometer

  3. Sphygmomanometer

  4. None of these


Correct Option: A
Explanation:

Ostwald viscometer is used to measure viscosity. Stalagmometer is used to measure surface tension. Sphygmomanometer is used to measure blood pressure.

At 0oC the density of Neon is

  1. maximum

  2. minimum

  3. 0

  4. None of these


Correct Option: A
Explanation:

At 0oC and 2 atm pressure, the density of neon is maximum. 

What is the main cause of cooling?

  1. Evaporation

  2. Sublimation

  3. Boiling

  4. None of these


Correct Option: A
Explanation:

Evaporation causes cooling. When a liquid evaporates, it absorbs the latent heat of vapourization from its surroundings to regain the energy lost during evaporation. This absorption of energy makes surrounding cool.

The surface tension of water ______ when the temperature is increased

  1. increases

  2. does not change

  3. decreases

  4. None of these


Correct Option: C
Explanation:

Surface tension decreases when temperature increases because cohesive forces decrease with an increase of molecular thermal activity. The influence of the surrounding environment is due to the adhesive action liquid molecules have at the interface.

Why water level in capillary increases?

  1. Due to surface tension

  2. Due to viscosity

  3. Due to vapour pressure

  4. None of these


Correct Option: A
Explanation:

Adhesion of water to the walls of a vessel will cause an upward force on the liquid at the edges and result in a meniscus, which turns upward. The surface tension acts to hold the surface intact. Capillary action occurs when the adhesion to the walls is stronger than the cohesive forces between the liquid molecules.

Which is the binding force in ionic crystal?

  1. Covalent band force

  2. Strong electrostatic force

  3. Weak Vander Waals force

  4. None of these


Correct Option: B
Explanation:

Ionic crystals are formed by a combination of highly electropositive ions (cations) and highly electronegative ions (anions). Thus, strong electrostatic force of attraction acts within the ionic crystals.

The osmotic pressure of 0.2 molar solution of urea at 27oC is

  1. 4.98 atm

  2. 1 atm

  3. 0.2 atm

  4. 27 atm


Correct Option: A
Explanation:

Osmotic pressure, π = cRT = 0.2 x 0.083 x 300 = 4.98 atm

Covalent crystals are

  1. hard

  2. soft

  3. very hard

  4. None of these


Correct Option: A
Explanation:

Covalent bonds are extremely strong, so covalent solids are very hard.

Iodine is a

  1. molecular solids

  2. metallic solids

  3. ionic solids

  4. None of these


Correct Option: A
Explanation:

Iodine is a molecular solid in which only one type of atoms of iodine are present.

Cu is a

  1. metallic solids

  2. ionic solids

  3. atomic solids

  4. covalent solids


Correct Option: A
Explanation:

Cu is a metallic solid.

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