Explore topic-wise InterviewSolutions in Current Affairs.

1. Chemical potential of water is called water potential. 

2. The Greek letter (ψ) psi represents water potential. 

3. The unit of measurement is in bars/pascals (Pa) or atmosphere. 

4. Water potential of pure water is always zero. 

5. Water potential of protoplasm is equal to D.PD. but it has a negative value. 

6. Water always moves from less negative potential to more negative water potential.

Halogens

The elements placed in group 7 (VIIA) of the periodic table are called halogens or salt producers. All these elements form salts called halides, e.g. NaCl, NaI, KCl, KI etc. Halogen is an ancient Greek word meaning 'salt producer'. Halogens have seven electrons in their valence shell and so are monovalent.

Transition Elements

All the elements belonging to 3 to 12 groups are called transition elements. They resemble each other in several physical and chemical properties. They are all metals. They are called transition elements because they are placed between the most reactive metals on the left and non-metals on the right. Their compounds are coloured. They exhibit variable valency.

 It is due to the formation of basic copper carbonate [CuCO₃.Cu(OH)₂]

The correct answer is (A) Adventitious roots

The correct answer is (C) an underground vertical stem.

Correct option is  (a) Darik

i. (d) Geobacter

ii. (d) Spinosad

iii. (a) Cider

iv. (d) Acetic

v. (a) Glass industry

vi. (b) sugar molasses

(1) Vinegar – Acetic acid

(2) Xanthan gum – Ice creams and puddings

pH of a solution is a measure of the H⁺ concentration in a solution. Lesser the pH, more acidic is the solution. Thus, rain water of city B is more acidic.

Magnesium hydroxide

(a) pH of city A /H of city B = (10^-6)/( 10^-5) = 1/10 

The ratio of hydrogen ion concentration in the two samples of rain water = 1:10 

(b) Increasing order of PH values : Lemon juice < Blood <NaOH solution.

(i) Solution of Na₂SO₄ is neutral, therefore, no colour change will be observed when red litmus paper is introduced in thus solution. 

(ii)The orange colour of methyl orange changes to red in dil. HCl

(iii)The colourless solution changes to pink when a drop phenolpthalein is added to solution of lime water.

(iv) Solution of ferric chloride is acidic; therefore, blue litmus will change to red in this solution.

Given solution Y turned blue litmus into red so, Y is an acid. 

Given solution ‘y’ turned red litmus into blue so, ‘y’ is a base. 

a) The reaction of an acid (x) with a base to give a salt and water.

b) When we put magnesium pieces in solution releases hydrogen gas. 

c) When zinc pieces are put in solution y, a chemical reaction will take place there. 

d) Acids contain more H+ ions in the given solutions, Y has more H+ ions because it is an acid.

The phenomenon, due to which salt formed by a weak acid and a strong base, or by a strong acid and a weak base, reacts with water to give an acidic or an alkaline solution, is known as salt hydrolysis.

(a) Acidic : Iron chloride, Copper sulphate

(b) Basic: Sodium carbonate, potassium acetate

(c) Neutral: Sodium chloride, sodium sulphate

(a) The solution turns to blue 

(b) CaO + H₂O → Ca(OH)₂ 

(c) Ca(OH)₂ is alkaline in nature

Sodium does not belong to the set. This is because all other elements belong to group 2 but sodium belongs to group 1 .

The acid which is present in baking powder is tartaric acid. Baking soda (sodium hydrogen carbonate) reacts to tartaric acid and forms CO₂ gas, water and sodium salt of acid. This CO₂ gas makes bread or cake soft and spongy.

NaHCO₃ + Acid → CO₂ + H₂O + Sodium salt of acid

Copper sulphate crystals contain water of crystallisaton. Water of crystallization is the fixed number of water molecules present in one formula unit of a compound. Copper sulphate crystal contains five water molecules in one formula unit. When we heat the copper sulphate crystals then this water is removed and the colour of crystals turn white.

 (A)  NaNH₂ + CH₃CH₂CH₂CH₂CH₂CH₃

On passing CO₂ gas through lime water, insoluble calcium carbonate is formed. On passing excess of CO₂, soluble calcium bicarbonate is formed.

Ca(OH)₂(aq)+CO₂(g) → CaCO₃(s) +H₂O(l)

CaCO₃(s)+CO₂(g) +H₂O(l) →  Ca(HCO₃)₂(aq)

Ca(HCO₃)₂(aq)- soluble

 CaCO₃ -  Insoluble

 (E)  All of the above

(a) Germanium (Ge) and Gallium (Ga)
(b) Group 14; Period 4 and Group 13; Period 4
(c) Ge - Metalloid; Ga - Metal
(d) Ga-3; Ge-4

(i) C and D are the two elements which are chemically similar. This is because the electronic configuration of C is 2,8,2 and that of D is 2,2 , so both the elements contains same number of valence electrons. 

(ii) Element B is an innert gas. This can be concluded by writing its electronic configuration as 2,8. Both the shells are completely filled. Thus it is an innert gas. 

(iii) The element E belongs to the 3^rd period. Its electronic configuration is 2,8,9 from which we can see that there are 3 shells present in it. So it belongs to 3^rd period. 

(iv) Element A is a non-metal. Its atomic number is 7, so its electronic configuration will be 2,5, we can see that it contains 5 valence electrons so it belongs to 15^th group and will lie on the right side of the second period. On moving from left to right in a period, non-metallic character increases. Thus A is a non-metal.

 The answer is (c) A and C

A and C are fluorine and chlorine belongs to the same group.

The answer is (c) A and C

A and C are fluorine and chlorine belongs to the same group.

● The electrons present in the outermost shell of an electron are known as valence electrons. 

● The number of valence electrons increases on moving from left to right in a period. This is because on moving from left to right the electrons are added in the same shell. 

● The valency of elements first increases in the period and then decreases. For example the trend of valency can be illustrated as follows:

(i) ● The electronic configuration of element A is: 2,8,1. Number of valence electrons=1 So, it belongs to 1^st group. 

● electronic configuration of element B is:2,8,4. It contains 4 valence electrons, so it belongs to 14^th group. 

● electronic configuration of element C is: 2,8,7. It contains 7 valence electrons, so it belongs to 17^th group. 

(ii) The element B is Si and it has a valency of 4. The element C is Chlorine and it has a valency of 1. So the formula of compound when B reacts with C is SiCl₄.

The number of shells is the same.

It is because HCl ionizes only in aqueous solution.

The types of elements are metals, nonmetals and metalloids.

The types of matter are solid, liquid, gas and plasma.

(a) H, He, Li, Be, B, C, N, O, F, Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K, Ca 

(b) Group 1 — H, Li, Na, K 

Group 2 — Be, Mg, Ca 

Group 13 — B, Al 

Group 14 — C, Si 

Group 15 — N, P 

Group 16 — O, S 

Group 17 — F, Cl 

Group 18 — He, Ne, Ar

The number of valence electrons is different for all these elements.

There is one valence electron in all these elements.

The smallest particles are called atoms.

Highest atomic number in period 2 is 10 which has an electronic configuration of 2,8. So, L shell is the outermost shell in period 2.

Carbon is the element which is essential constituent of all organic compounds and lies in group 14.

The answer is (d) P

• Electronic configuration of Na, Al, Si and P are 2,8 1, 2,8,3,2,8,4, and 2,8,5 respectively. 
• Valence electrons in Na, Al, Si and P are 1,3,4 and 5.
• Hence phosphorus has maximum number of valence electrons.

a. Boyle’s law 

b. Charles’ law 

c. Avogadro’s law 

[Note : Assuming, T constant]

Inbreeding depression refers to the reduced fertility and productivity associated with continued breeding.

It is the manipulation of plant species so as to create new improved varieties that are better suited for cultivation, give better yield and are resistant to damage from pest and pathogens.

Callus is an unorganised undifferentiated mass of actively dividing cells.

The method of producing very large number of plants through tissue culture is known as micro-propagation.

Single Cell Protein.

Embryos which normally don’t survive inside seeds can be grown in tissue culture to form new plants. This process is called embryo rescue.

Crescograph developed by Sir J.C. Bose.