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(b) P, Si, Al, Na

Sodium metal test: Add a small piece of sodium metal to the organic liquid (to be tested), taken in a dry test tube. If bubbles (or effervescence) of hydrogen gas are produced, it indicates that the given organic liquid is an alcohol.

(a) A carboxylic acid reacts with sodium hydrogencarbonate to give brisk effervescence of carbon dioxide gas but an alcohol does not react with sodium hydrogencarbonate.

Soaps are biodegradable whereas detergents are non-biodegradable.

(a) Acid test: Reaction with carbonates/hydrogen carbonates. Take samples of alcohol and carboxylic acid in 2 test tubes, and add sodium carbonate or sodium bicarbonate solution to each. The compound which will produce brisk effervescence of CO₂ gas will be acid. 

(b) Alcohol test: Take small amount of ethanol and ethanoic acid in test tube A and B. Add 5% solution of alkaline potassium permanganate drop by drop to this solution and warm the test tube. 

The colour of potassium permanganate will disappear in test tube containing alcohol.

Value of v/c = 0.44

Given that |(15 - x,1,10),(11 - 3x,1,16),(7 - x,1,13)| = 0

or, |(15 - x,1,10),(-4 - 2x,0,6),(-8,0,3)| = 0

or, (-1)(-12 - 6x + 48) = 0 

or, 6x - 36 = 0

∴ x = 6

A. (ii) 

B. (iv) 

C. (v) 

D. (iii) 

E. (i)

A. (iii) 

B. (iv) 

C. (v) 

D. (i)

E. (ii)

Oil used in Froth floatation method is pine oil

(b) Aluminium

Pranayama is a type of traditional breathing exercise. 1f it should be regular, it can increase the capacity of lungs to take more air, thus more oxygen can be supplied to the body cells resulting in release of more energy. We became more energetic and can do whatever we wish to do.

We take air through our nostrils, when we inhale air, it passes though our nostrils into the nasal cavity. From the nasal cavity, the air reaches our lungs through the windpipe. Lungs are present in the chest cavity. This cavity is surrounded by ribs on the sides. A large muscular sheet is called diaphragm forms the floor of the chest cavity. During inhalation ribs move up and outwards and diaphragm moves down, this movement increase space in our chest cavity and air rushes into the lungs. The lungs get filled with air, During exhalation, ribs move down and inwards, while diaphragm moves up to its former position. This reduces the size of the chest cavity and air is pushed out of the lungs. Like this we are breathing.

1. d. Hydrogen

2. a. 1

3. b. Radium

4. c. H

5. b. Hydrogen peroxide

The biodiversity should be conserved because of the following reasons:

i. Narrowly utilitarian arguments for deriving direct economic benefit from nature. 

ii. Broadly utilitarian arguments as biodiversity plays a major role in many ecosystem services. 

iii. Ethical reasons: There is a need to realise that every species has an intrinsic value and we need to pass on our biological legacy to future generations.

It can be inferred that Western Ghats have a greater species diversity.

The Correct option is: B 

Rutherford proposed that the atomic nucleus is positively charged.

(a) It is a sodium salt of long-chain fatty acids

Newlands arranged the elements in the order of increasing atomic masses.

(a) L shell can accommodate maximum of 8 e-. 

(b) N shell can accommodate maximum of 32 e-.

Correct option (C) Both Q and R give white precipitate with AgNO₃ solution dissolved in NH₄OH. 

Explanation: 

Only alkynes give white precipitate with AgNO₃ solution dissolved in NH₄OH.

P is C₂H₆, Q is C₂H₄ and R is C₂H_2.

The Correct option is (C)

(c) fatty acid

TFM – Total Fatty Matter. It corresponds the fatty acid (oil).

Correct option  (D) IV only

Explanation: 

lsomers have same molecular formula, empirical formula and general formula but different structural formulae.

(a) (NH₄)₂ SO₄ (or) (NH₄)₃ PO₄ 

C_nH_2n-2  is a general formula for alkyne.

He failed to arrange all the elements in triads having same chemical properties.

Correct option  (C) (i), (ii) and (iv) only 

Explanation: 

For atomic number 6, the electronic configuration is 2, 4 and it is carbon atom. Carbon has 4 valence electrons and, it is a member of group 14 in the periodic table. All the elements in this group have similar electronic configurations hence, have same number of valence electrons.

(b) Be, Mg, Cr

Correct option  (B) P is a non-metal while R is a metal. 

Explanation: 

P, Q and R have consecutive increasing atomic numbers. As noble gases are present at the end of each period, P must be a non-metal of the same period and R must be a metal of the next period.

(b) Cu, Au, Ag

(a) 9. 

(b) 17 Cl. 

(c) Both have the same number of valence electrons (7 electrons each) in their atoms.

(c) They are radioactive in nature

We will first write the electronic configuration of all the elements mentioned: 

17: - 2,8,7 

10: - 2,8 

20: - 2,8,8,2 

12: - 2,8,2 

19: - 2,8,8,1 

15: - 2,8,5 

So, the elements with atomic number 

17, 12, 15 belong to the same period as they have the same number of the shell. 

20, 19 belong to the same period as they have the same number of the shell.

(i) X and Z.

X and Z have zero valency hence they belong to same group: noble gases.

(ii) Y and Z. Y: 

2,4 and Z: 2,8 so, both of them belong to second period with two shells filled.

B, C, D element with atomic number 3, 11, 15, 18, 19 respectively belong to the same group.

(i) The number of valence electrons increases from 1 to 2 in the 1st period of the periodic table.

(ii) The valence electrons increase from 1 to 8 in the 2nd period of the periodic table.

Correct option  (D) Q, R and T

Explanation: 

Tendency to lose electrons increases down the group hence, Q will have maximum tendency to lose electrons. Tendency to gain electrons decreases down the group hence, R has maximum tendency to gain electrons. T is a noble gas hence, it has no tendency to gain or lose electron.

(a) Since sodium hydroxide and sulphuric acid are both soluble, an excess of either of them cannot be removed by filtration. Therefore it is necessary to find out on small scale, the ratio of solutions of the two reactants. 

(b) As iron chloride is highly deliquescent, so it is kept dry with the help of fused calcium chloride.

The valency of elements increases from 1 to 4 and then decreases to zero in the 3rd period.

Correct option  (C) I and II only 

Explanation: 

The atomic radii decrease along a period from left to right and isotopes are not given separate places in the periodic table as they have same atomic number.

(1) Noble gas – Helium 

(2) First period – Two elements 

(3) Second period – Eight elements

(4) 3^rd period – 18 elements.

(B) Both statements 1 and 2 are true but statement 2 is not the correct explanation of statement 1 .

(1) Helium – Zero group 

(2) Horizontal row – Period 

(3) Group I – Alkali metal 

(4) Group II – Alkaline earth metal.

(1) s-block elements – Groups 1, 2

(2) p-block elements – Groups 13 to 18

(3) d-block elements – Groups 3 to 12

(4) f-block elements – Lanthanides and actinides.

Correct option  (A)

Explanation: 

 Element 'P' belongs to group 2 and period 3, so it should be magnesium (Mg).

Element 'Q' belongs to group 16 and period 2, so it should be oxygen (O).

Element 'R' belongs to group 18 (noble gases) and period 2, so it should be neon (Ne).

Element 'T' belongs to group 15 and period 3, so it should be phosphorus (P).

Element 'U' belongs to group 18 and period 3, so it should be argon (Ar).

Correct option  (C) (a) - (iii), (b) - (iv), (c) - (i), (d) - (ii) 

Explanation: 

Fluorine being a non-metal and smaller in size, has the highest electronegativity. Chlorine has highest electron afflnity than fluorine due to interelectronic repulsions between the added electron and the other electrons in the electron cloud of small sized F atom. Caesium has highest electropositivity as it is an alkali metal having large atomic size and high metallic character. Ruthenium being a transition element shows highest oxidation number.

Electronic configuration of
Nitrogen : 2,5
Oxygen: 2, 6
Fluorine: 2.7
(a) Fluorine (F) is most electronegative and nitrogen (N) is least electronegative.
(b) Fluorine (F) has 7 valence electrons.
(c) Valency of nitrogen is 3 and 5. valency of oxygen is 2, valency of fluorine is 1.