Explore topic-wise InterviewSolutions in Current Affairs.

C) Both A and B

B) PCl₅ ⇌ PCl₃+ Cl₂ 

C) displacement

B) tyrosinase

Correct option is C) C

(i) When fats and oils are oxidised, they become rancid and their smell and taste changes.

(ii) To prevent spoilage of food, special types of substances called antioxidants are added to fatty foods.

(iii) Chips are packed in packets flushed with nitrogen to prevent spoilage by oxidation.

(i) H- bonding

(ii) Dipole-dipole forces

Society is a group of individuals, families, neighbors and institutions.

(a) H₂O and alcohol - Hydrogen bonding

(b) Cl₂ and CCl₄,- London forces

(c) He and He atoms - van der Waals forces

(d) Na⁺ ion and H₂O Dipole-dipole forces

(e) HBr and HBr- Dipole - dipole forces

These are called social institutions. 

For example – marriage, family, caste, etc.

(a) noble gases. 

(b) between HCl molecules. 

(c) Between water molecules or HF molecules. 

(d) Between NO_3- and water molecules.

a. Threshing

The process of solid changing directly in to vapour from without becoming liquid is called Sublimation.

Air is a Mixture.

(d) Chlorine

Correct option is (a) Two

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

Because inter molecular forces are strong enough to hold the molecules but not so strong as to fix them into definite position.  

(c) Rain water

This is because the intermolecular forces of attraction are strong enough to hold the molecules together but not so strong as to fix them into definite positions (as in solids). Instead, they possess fluidity and hence no definite shape.

(d) They have definite shape and size.

Because inter molecular forces are strong enough to hold the molecules but not so strong as to fix them into definite position.

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

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

Water has maximum density at 4°C because when temperature is increased from o to 4°C, some of the H-bonds break and molecules come closer and density increases till 4°C because volume decreases. But, above 4°C, the kinetic energy of molecules increases which leads to increase in volume and density decreases.

Hydrogen bonding affect the physical properties of compounds. Ice is H-bonded molecular solid having open cage structure whereas liquid water has H-bonding having closed cage structure that is why ice has lower density than water.

Groundnut oil is unsaturated in nature.

(i) The critical temperature CO₂ is 304 K and its critical pressure is 73 atm. Therefore, in a tank of CO₂ above its critical temperature and pressure, the liquid & gas phases of CO₂ are replaced by a single phase called the supercritical carbon dioxide. Although supercritical CO₂ is a gas, it being very dense can be used as a solvent. 

(ii) Supercritical carbon dioxide and other supercritical fluids have gained importance in recent times because of the possibility of replacing toxic and environmentally unfriendly solvents for extraction of organic compounds from natural sources. 

(iii) These days the most common solvent used for dry cleaning clothes is perchloroethylene, Cl₂C = CCl₂ but is an air pollutant. Therefore, clothes can be dry cleaned with supercritical carbon dioxide if we use a special detergent. 

(iv) Although carbon dioxide is a greenhouse gas, but the gas once used can be recirculated and not allowed to escape into the atmosphere. Consequently, its impact on global warming will be negligible.

When an ester reacts with water in presence of a base, a salt of carboxylic acid and an alcohol are produced. Such a reaction is called saponification.

For example: When ethyl ethanoate is heated with a solution of sodium hydroxide, sodium ethanoate and ethanol are produced.

CH₃COOC₂H₅+NaOH+Boil  → CH₃COONa+C₂H₅OH.

Butter is mostly made up of heart-healthy saturated fat and is low in polyunsaturated fat. Saturated fats are good for health. A vegetable oil is a triglyceride extracted from a plant, that are liquid at room temperature. Their oil contain very large amounts of biologically active fats called Omega-6 polyunsaturated fatty acids, which are harmful in excess.

Ethane is formed when hydrogen is added to ethene.

The 5% – 10% aqueous solution of acetic acid is called vinegar.

Homologous series is a series of organic compounds having same general formula, all members of the compounds show same chemical properties and slight gradation in physical properties.

Synthetic detergent is non-biodegradable, it remains in the water thereby causing water pollution.

Detergents form lather with both hard and soft water hence we cannot distinguish between them.

1. Some synthetic detergents resist biodegradation, i.e. they are not decomposed by micro-organisms such as bacteria. 

2. Hence, they cause water pollution in lakes and rivers.

3. They tend to persist for a long time, making the water unfit for aquatic life.

Doing one thing at a time and that too at its best, is the golden rule of doing work.

a. We should not waste even a single moment to succeed in life.
b. I was happy to see my friend.
c. We should always follow the traffic rules.
d. We should never tell a lie.

I learnt that we should not waste time uselessly and should concentrate on one work at a time for good result.

• never
• kite
• done
• yell
• day

When a child is given sufficient time to work and plays it makes the child happy.

a. She fell down and cried a lot last night.
b. Yesterday Dipti’s mother cooked special food.
c. Rekha saw an elephant last week.
d. Kabir walked very fast to catch the bus.

He gave the judgement that the bird did not belong to Devadatta as he had shot it. It rightly belonged to Siddhartha as he had saved it.

Siddhartha’s cousin Devadatta shot the swan.

(c) River valleys

Correct Answer is: (a) Ganga

गेहूँ और चावल की अधिक पैदावार वाली किस्मों के कारण ढेरियों का आकार शिखरों को छू गया, जिसके कारण हरित क्रान्ति के समय 1970 के दशक में दानों की पैदावार बढ़ गई और इनको सम्भालना मुश्किल हो गया।