Science Delhi Set 2 2022-2023 English Medium Class 10 Question Paper Solution

When sodium bicarbonate reacts with dilute hydrochloric acid, the gas evolved is ______.

Hydrogen; it given pop sound with burning match stick.

Hydrogen; it turns lime water milky.

Carbon dioxide; it turns lime water milky.

Carbon dioxide; it blows off a burning match stick with a pop sound.

When aqueous solutions of potassium iodide and lead nitrate are mixed an insoluble substance separates out. The chemical equation for the reaction involved is: 

\[\ce{KI + PbNO_3 ->PbI + KNO3}\]

\[\ce{2KI + Pb(NO_3)2 ->PbI2 + 2KNO3}\]

\[\ce{KI + Pb(NO_3)2 ->PbI + KNO3}\]

\[\ce{KI + Pb(NO_3)2 ->PbI2 + 2KNO3}\]

A metal ribbon 'X' bums in oxygen with a dazzling white flame forming a white ash 'Y'. The correct description of X, Y and the type of reaction is:

X = Ca; Y = CaO;

Type of reaction = Decomposition

X = Mg; Y = MgO;

Type of reaction = Combination

X = Al; Y = Al₂O₃;

Type of reaction = Thermal decomposition

X = Zn; Y = ZnO;

Type of reaction = Endothermic

Acid present in tomato is ______.

Methanoic acid 

Acetic acid 

Lactic acid 

Oxalic acid

Sodium hydroxide is termed an alkali while Ferric hydroxide is not because ______.

Sodium hydroxide is a strong base, while Ferric hydroxide is a weak base.

Sodium hydroxide is a base which is soluble in water while Ferric hydroxide is also a base but it is not soluble in water. 

Sodium hydroxide is a strong base while Ferric hydroxide is a strong acid.

Sodium hydroxide and Ferric hydroxide both are strong base but the solubility of sodium hydroxide in water is comparatively higher than that of Ferric hydroxide.

The name of the salt used to remove permanent hardness of water is ______.

Sodium hydrogen carbonate (NaHCO₃) 

Sodium chloride (NaCl) 

Sodium carbonate decahydrate (Na₂CO₃.10H₂O)

Calcium sulphate hemihydrate (CaSO₄.`1/2`H₂O)

The electron dot structure of chlorine molecule is:

Observe the following diagram and identify the process and its significance from the following options:

Evaporation: maintains water contents in leaf cells. 

Transpiration: creates a suction force which pulls water inside the plant.

Excretion: helps in excreting out waste water from the plant. 

Translocation: helps in transporting materials from one cell to another.

During adolescence, reproductive phase starts and ______.

general growth rate begin to show down

height becomes less

the body weight is reduced

hair growth decreases

Which pair of sex chromosome will determine a male?

XO

XX

XY

YY

One of the events that does not occur during photosynthesis is ______.

Chlorophyll absorbs solar energy.

Carbon dioxide is released during the process.

Oxygen is released during the process.

Carbon dioxide is absorbed during the process.

The number of chromosomes in parents and offsprings of a particular species undergoing sexual reproduction remain constant due to:

doubling of chromosomes after zygote formation.

the halving of chromosomes during gamete formation.

doubling of chromosomes after gamete formation.

the halving of chromosomes after gamete formation.

Two LED bulbs of 12W and 6W are connected in series. If the current through 12W bulb is 0.06A the current through 6W bulb will be ______.

0.04 A

0.06 A

0.08 A 

0.12 A

The correct pattern of magnetic field lines of the field produced by a current carrying circular loop is:

The resistance of a resistor is reduced to half of its initial value. If other parameters of the electrical circuit remain unaltered, the amount of heat produced in the resistor will become ______.

four times

two times

half

one forth

Two LED bulbs of 10W and 5W are connected in series. If the current flowing through 5W bulb is 0.005A, the current flowing through 10W bulb is ______.

0.02 A

0.01 A

0.005 A

0.0025 A

Assertion (A): Reaction of Quicklime with water is an exothermic reaction. 

Reason (R): Quicklime reacts vigorously with water releasing a large amount of heat.

Both (A) and (R) are true and (R) is the correct explanation of (A).

Both (A) and (R) are true but (R) is not the correct explanation of (A).

(A) is true, but (R) is false.

(A) is false, but (R) is true.

Assertion (A): In humans, if gene (B) is responsible for black eyes and gene (b) responsible for brown eyes, then the colour of eyes of the progeny having gene combination Bb, bb or BB will be black only.

Reason (R): The black colour of the eyes is a dominant trait.

Both (A) and (R) are true and (R) is the correct explanation of (A).

Both (A) and (R) are true but (R) is not the correct explanation of (A).

(A) is true, but (R) is false.

(A) is false, but (R) is true.

Assertion (A): The inner walls of the small intestine have finger like projections called villi which are rich in blood. 

Reason (R): These villi have large surface area to help the small intestine in completing the digestion of food.

Both (A) and (R) are true and (R) is the correct explanation of (A).

Both (A) and (R) are true but (R) is not the correct explanation of (A).

(A) is true, but (R) is false.

(A) is false, but (R) is true.

Assertion (A): A current carrying straight conductor experiences a force when placed perpendicular to the direction of magnetic field.

Reason (R): The net charge on a current carrying conductor is always zero.

Both (A) and (R) are true and (R) is the correct explanation of (A).

Both (A) and (R) are true but (R) is not the correct explanation of (A).

(A) is true, but (R) is false.

(A) is false, but (R) is true.

State the essential function performed by ozone at the higher levels of the atmosphere.

Why was there a sharp in the amount of ozone in the atmosphere in 1980's.

Name the part of brain which is responsible for following actions: 

1. Maintaining posture and balance
2. Beating of heart
3. Thinking
4. Blood pressure

Where are auxins synthesized in a plant? Which organ of the plant shows: 

1. Positive phototropism
2. Negative geotropism
3. Positive hydrotropism

Write one specific function each of the following organs in relation with excretion in human beings: 

1. Renal Artery
2. Urethra
3. Glomerulus
4. Tubular part of nephron

Give two reasons, why bile juice is considered to be an important secretion of liver in the process of digestion?

Name the hormone secreted in scary situations by animals. Write any three responses which enable the animal body to deal with it.

Use of several pesticides which results in excessive accumulation of pesticides in rivers of ponds, is a matter of deep concern. Justify this statement. 

While electrolysing water before passing the current some drops of an acid are added. Why? Name the gases liberated at cathode and anode. Write the relationship between the volume of gas collected at anode and the volume of gas collected at cathode.

What is observed when silver chloride is exposed to sunlight? Give the type of reaction involved.

Suggest a safe procedure of diluting a strong concentrated acid. 

Name the salt formed when sulphuric acid is added to sodium hydroxide and write its pH.

Dry HCl gas does not change the colour of dry blue litmus paper. Why?

List two difference in the characteristic properties of the virtual images formed by the two types of spherical lenses (concave and convex). How are these characteristics of the two lenses use in the correction of the two common defects of vision namely myopia and hypermetropia?

An object is kept at a distance of 1m from a lens of power +2D:

1. Identify the type of lens.
2. Calculate its focal length and distance of the image formed.

Define the following terms in the context of a diverging mirror:

1. Principal focus
2. Focal length

Draw a labelled ray diagram to illustrate your answer.

The power of a lens is +4D. Find the focal length of this lens. An object is placed at a distance of 50 cm from the optical centre of this lens. State the nature and magnification of the image formed by the lens and also draw a ray diagram to justify your answer.

Why is acidified water considered to be a good conductor of electricity?

Write a chemical equation showing the ionic products formed on dissolving potassium hydroxide in water.

Care must be taken while diluting concentrated nitric acid with water. Why?

Write one difference between biodegradable and non-biodegradable wastes. List two impacts of each type of the accumulated waste on environment if not disposed off properly.

Draw the structure of butanoic acid.

Draw the structure of the following compound:

Chloropentane

How are structure (i) and structure (ii) given below related to one another? Give reason to justify your answer.

Structure (i) \[\begin{array}{cc} \ce{CH3}\phantom{............}\ce{CH3}\\ \backslash\phantom{..........}/\\ \ce{CH - CH}\\ /\phantom{..........}\backslash\\ \ce{CH3}\phantom{............}\ce{CH3} \end{array}\]

Structure (ii) \[\begin{array}{cc} \ce{CH3}\phantom{...........}\\ \backslash\phantom{.......}\\ \ce{CH3 - C - CH2CH3}\\ /\phantom{.......}\\ \ce{CH3}\phantom{...........} \end{array}\]

Differentiate between saturated and unsaturated carbon compounds on the basis of their general formula.

What happens when a small piece of sodium is dropped in ethanol? Write the equation for this reactions.

Why is glacial acetic acid called so?

What happens when ethanol is heated at 443K in the presence of conc. H₂SO₄? Write the role of conc. H₂SO₄ in this case.

Write an equation showing saponification.

Name and explain the two modes of asexual reproduction observed in hydra.

What is vegetative propagation? 

List two advantages of vegetative propagation technique.

It is observed that covalent compounds are had conductors of electricity. Give reason. 

Carbon can neither form C^4- cation nor C⁴ anion. Why?

Draw electron dot structure of Ethanol.

Identify heteroatom (s) in the following compound.

\[\begin{array}{cc}
\ce{CH3CH2 - C - CH3}\\\
\phantom{....}||\
\ce\\\phantom{....}{O}\end{array}\]

Identify heteroatom (s) in the following compound.

\[\ce{CH3CH2Cl}\]

What are soaps?

Explain the mechanism of cleansing action of soap with the help of a labelled diagram.

Detergents are better than soaps. Justify.

The melting points and boiling points of some ionic compounds are given below:

These compounds are termed ionic because they are formed by the transfer of electrons from a metal to a non-metal. The electron transfer in such compounds is controlled by the electronic configuration of the elements involved. Every element tends to attain a completely filled valence shell of its nearest noble gas or a stable octet.

1. Show the electron transfer in the formation of magnesium chloride.
2. List two properties of ionic compounds other than their high melting and boiling points.
3. (A) While forming an ionic compound say sodium chloride how does sodium atom attain its stable configuration?
   OR
   (B) Give reasons:
   (i) Why do ionic compounds in the solid state not conduct electricity?
   (ii) What happens at the cathode when electricity is passed through an aqueous solution of sodium chloride?

1. Why an offspring of human being is not a true copy of his parents in sexual reproduction? 
2. While performing experiments on inheritance in plants, what is the difference between F₁ and F₂ generation?
3. (A) Why do we say that variations are useful for the survival of a species over time?
   OR
   (B) Study Mendel's cross between two plants with a pair of contrasting characters.
   

   RRYY	× rryy
   Round Yellow	Wrinkled Green

   He observed 4 types of combinations in F₂ generation. Which of these were new combinations? Why do new features which are not present in the parents, appear in F₂ generation?

1. Determine the speed of light in diamond if the refractive index of diamond with respect to vacuum is 2.42. Speed of light in vacuum is 3 × 10⁸ m/s. 
2. Refractive indices of glass, water and carbon disulphide are 1.5, 1.33 and 1.62 respectively. If a ray of light is incident in these media at the same angle (say θ), then write the increasing order of the angle of refraction in these media. 
3. (A) The speed of light in glass is 2 × 10⁸ m/s and is water is 2.25 × 10⁸ m/s.
   (a) Which one of the two optically denser and why?
   (b) A ray of light is incident normally at the water glass interface when it enters a thick glass container filled with water. What will happen to the path of the ray after entering the glass? Give reason. 
   OR
   (B) The absolute refractive indices of glass and water are 4/3 and 3/2, respectively. If the speed of light in glass is 2 × 10⁸ m/s, calculate the speed of light in (i) vacuum (ii) water.