Explore topic-wise InterviewSolutions in .

1) A is wrong because when we move from left to right the atomic number increases. So, the nuclear attraction over outermost orbital increases. Therefore the atomic size decreases. 

2) B is correct but it does not follow a regular trend in a period. 

3) C is correct. As move from top to bottom in a group atomic size increases. Therefore it is easy to lose electrons. So electropositive character increases. 

4) D is wrong because as we move from top to bottom in a group atomic size increases. So electronegativity decreases.

1. Solids have a definite shape and volume. 

2. Most of the solids are rigid while some are plastic and some elastic. 

3. Solids have practically negligible compressibility, i.e., their volume is not very much changed by external forces.

Examples of liquid in liquid: 

Vinegar, dilute sulphuric acid.

The property by which solids maintain their shapes when subjected to external forces is called rigidity.

Some solids are deformed by external forces and do not regain their original shapes on removal of the forces. This property of solids is called plasticity.

Examples of gas in gas: Air, cooking gas.

Correct option is (c) Chlorophyll

A substance which does not have a definite shape, but has a definite volume is called a liquid.

Examples of solid in solid: Brass, stainless steel.

Correct option is (c) rigidity

1. The forces among the constituent particles (atoms/molecules) are called intermolecular forces. 

2. In solids these forces are strong enough to keep the particles together in fixed positions, as a result solids have a high density and negligible compressibility

Some solids undergo a change in their shapes and volume when subjected to external forces and regain their original shapes and volume on removal of the forces. This property of solids is called elasticity.

A substance which has a definite shape and volume is called a solid.

Correct option is (d) elasticity

The different states of matter are solid, liquid and gas.

Two principal ways of classifying matter are:

1. On the basis of physical state as a solid, liquid or gas. 

2. On the basis of chemical constitution as an element, compound or mixture.

Correct option is (c) heterogeneous mixture

(i) When all the components of a mixture form one phase, it is called homogeneous mixture.

(ii) Milk is a mixture of water, lactose, fats and proteins.

(iii) The intermolecular force is very weak in the gaseous state.

Correct option is (c) chemical composition of matter

The part of matter with uniform composition is called a phase.

The different types of solutions:

• Liquid in liquid. Examples: Vinegar, dilute sulphuric acid. 
• Gas in gas. Example: Air. 
• Solid in solid. Examples: Brass, stainless steel, bronze. 
• Gas in liquid. Examples: Chlorinated water.

When all the components of a mixture form one phase, it is called homogeneous mixture. 

Example: Solution of blue vitriol in water, solution of sugar in water.

• Homogeneous solution: Soda water, potassium permanganate solution, alcohol in water. 
• Heterogeneous solution: Milk, ink solution, wheat flour in water.

The mixture of oil in water is a heterogeneous mixture.

(i) Silicon, arsenic.

(ii) Sodium (Na), potassium (K), chlorine (Cl).

(iii) Magnesium (Mg), Calcium (Ca).

1. Molecular formula of potassium chloride: KCl 

2. Molecular formula of sodium sulphide: Na₂S.

The intermolecular force is very weak in gases. The distance between the particles of gas is very large. They move freely and occupy all the available space.

The term chromatography was originally derived from the Greek word chroma meaning colour and graphy meaning writing because the method was first used for the separation of coloured substances (plant pigments) into individual components. Now the term chromatography has lost its original meaning and the method is widely used for separation, purification and characterization of the components of a mixture whether coloured or colourless.

Inferences:

1. When heat is added (or removed) during a change of state, the temperature remains constant.

2. Also the slopes of the phase lines are not all the same, which indicates that specific heats of the various states are not equal.

3. For water, the latent heat of fusion and vaporisation are L_f = 3.33 × 10⁵ J kg^-1 and L_v = 22.6 × 10⁵ J kg^-1 respectively,

i.e., 3.33 × 10⁵ J of heat is needed to melt 1 kg of ice at 0 °C and 22.6 × 10⁵ J of heat is needed to convert 1 kg of water to steam at 100 °C.

4. This means, steam at 100 °C carries 22.6 × 10⁵ J kg^-1 more heat than water at 100 °C.

• The curve labelled l – v represents those points where the liquid and vapour phases are in equilibrium.
• It is a graph of boiling point versus pressure.
• The l – v curve of water correctly shows that at a pressure of 1 atmosphere, the boiling point of water is 100 °C and the boiling point gets lowered for a decreased pressure.
• The l – v curve for CO₂ yields that CO₂ cannot exist as a liquid under normal atmospheric pressure conditions.
• The curve l – s represents the points where the solid and liquid phases coexist in equilibrium.
• It is a graph of the freezing point versus pressure.
• At one standard atmosphere pressure, the freezing point of water is 0 °C which can be depicted using l – s curve of water.
• At a pressure of one standard atmosphere water is in the liquid phase if the temperature is between 0 °C and 100 °C but is in the solid or vapour phase if the temperature is below 0 °C or above 100 °C.
• Also, l – s curve for water slopes upward to the left i.e., fusion curve of water has a slightly negative slope.
• This is true only of substances that expand upon freezing.
• However, for most materials like CO₂, the l – s curve slopes upwards to the right i.e., fusion curve has a positive slope. The melting point of CO₂ is -56 °C at higher pressure of 5.11 atm.
• The curve labelled s – v is the sublimation point versus pressure curve.
• Water sublimates at pressure less than 0.0060 atmosphere, while carbon dioxide, which in the solid state is called dry ice, sublimates even at atmospheric pressure at temperature as low as -78 °C.
• The temperature and pressure at which the fusion curve, the vaporisation curve and the sublimation curve meet and all the three phases of a substance coexist is called the triple point of the substance.
• The triple point of water is that point where water in solid, liquid and gaseous states coexist in equilibrium and this occurs only at a unique temperature and pressure.
• The triple point of water is 273.16 K and 6.11 × 10^-3 Pa and that of CO² is -56.6 °C and 5.1 × 10^-5 Pa.

1. Latent heat of fusion:

• The quantity of heat required to convert unit mass of a substance from its solid state to the liquid state, at its melting point, without any change in its temperature is called its latent heat of fusion.
• The S.I. unit of latent heat of fusion is J/kg and its C.G.S. unit is cal/’g.

2. Latent heat of vaporisation:

• The quantity of heat required to convert unit mass of a substance from its liquid state to vapour state, at its boiling point, without any change in its temperature is called its latent heat of vaporisation.
• The S.I. unit of latent heat of vaporization is J/kg and its C.G.S unit is cal/g.

Correct option is: (B) J kg^-1

1. The energy required to completely separate the molecules or atoms in liquids is greater than the energy needed to break the rigidity (rigid bonds between the molecules or atoms) in solids.

2. Also, when the liquid is converted into vapour, it expands. Work has to be done against the surrounding atmosphere to allow this expansion. 

Hence, latent heat of vaporisation is larger than latent heat of fusion.

1. Latent heat of a substance is the quantity of heat required to change the state of unit mass of the substance without changing its temperature.

2. Mathematically, if mass m of a substance undergoes a change from one state to the other then the quantity of heat absorbed or released is given by, Q = mL

where. L is known as latent heat.

3. It is characteristic of the substance.

4. Its SI unit is J/kg.

5. The value of L depends on the pressure and is usually quoted at one standard atmospheric pressure.

(a) (i) Ammonium cyanate, NH₄CNO

(ii) Urea, CO(NH₂)₂

(b) The molecular formula of butane is C₄H₁₀ ; Its isomers are n-butane and 2-methylpropane; LPG.

• By bio decomposition 
• Through fertilizers 
• By nitrogen-fixing by bacteria

Correct Answer is: (d) 0.033M

Osmotic Pressure (Π) is given by:

Π= CRT

(Where C is concentration, R is gas constant, T is temperature)

Given, Π = 0.0821 atm

T = 300K

Then using above equation,

C = 0.0821÷ (0.0821×300) mole per Litre

C= 0.003333333 moles per litre

Correct Answer is: A. NaOH 

• Caustic soda is one of the common names for sodium hydroxide (NaOH), which is also known aslye. 

• Its common name derives from its chemical identity as a sodium hydrate and because it is caustic or corrosive. 

• In pure form, caustic soda is a waxy, white solid. It readily absorbs water and forms aqueous solutions

The Correct option is A. NaOH

Correct Answer is:A. Solution of CO₂ gas in water 

Soda water is a liquid solution of water and carbon dioxide gas. Gas can be dissolved in water if the water's temperature is fairly low.

Answer is (A) Solution of CO₂ gas in water

Answer is (B) PbO₂

Correct Answer is: A. PbO 

PbO is used to protect iron from rusting

Correct Answer is: (A) Oxidizing agen

• PCl₅ can act as an oxidizing agent not as the reducing agent. 

• The highest oxidation state that P can show is +5. In PCl₅, phosphorus is in its highest state (+5). 

• However, it can decrease its oxidation state and act as an oxidizing agent.

Correct Answer is: B. F 

Among halogens, fluorine is the strongest oxidising agent. It has highest value of oxidation potential.

Correct Answer is: (C) Empty d-orbital 

A good Oxidising agent reduces itself i.e. it gains electrons from others. It tends to gain one more electrons to acquire stable electronic configuration.

(A) Oxidising agent

The Correct option is B. F