Explore topic-wise InterviewSolutions in Current Affairs.

Shiv Sena, Maharashtra Navnirman Sena, Vanchit Bahujan Aghadi, Rashtriya Samaj Paksha.

The fruit may be a citrus fruit or its juice may contain an acid, that is why the traces of acid remained in the knife that turned the blue litmus red

(d) all the above

1) Baking powder is a mixture of baking soda and a mild edible acid such as tartaric acid. When baking powder is heated or mixed in water, the following reaction takes place.

2) Carbon dioxide produced during the reaction causes bread or cake to rise making them soft and spongy.

3) Sodium hydrogen carbonate is also an ingredient in antacids. Being alkaline, it neutralizes excess acid in the stomach and provides relief.

4) It is also used in soda-acid, fire extinguishers. 

5) It acts as mild antiseptic.

Aspirin is used in the prevention of heart attacks.

1. It is used for bleaching cotton and linen in the textile industry for bleaching wood pulp in paper industry and for bleaching washed clothes in laundry. 

2. Used as an oxidizing agent in many chemical industries. 

3. Used for disinfecting drinking water to make it free of germs. 

4. Used as a reagent in the preparation of chloroform.

Some special Substances which are used to test whether a substance is acidic or basic very easily are called as indicators.

(a) acetyl salicylic acid

(a) (i) Acids; A, C and D.

(ii) Alkalis; B, E and F.

(b) (i)Sulphuric acid.

(ii) Sulphuric acid.

(iii) Sodium hydroxide.

(iv) Nitric acid.

The strength of an acid (or) an alkali can be tested by using pH value of a solution. If the value of a pH of a solution is less, then that solution exhibits acidic nature. 

If the value of a pH of a solution is more, then that solution exhibits basic nature. 

pH value of a solution “X” is 13 

pH value of a solution “Y” is 6 

pH value of a solution “Z” is 2 

a) Solution ‘Z’ is strong acid because its pH is 2. 

b) Among given solutions, solution X is weakest acid. Weak solution contains ions along with molecules of solution. So X exhibits like this character. 

c) Solution X is strong base. Because its pH is 13. 

d) If base is added to solution ‘Z’, then its pH will increase.

1. Distilled water 

2. Milk of Magnesia 

3. Gastric juice 

4. Pink

Turmeric, litmus, china rose petals etc., are some of the natural indicators.

(b) paracetamol

The solutions which do not change the colour of either red or blue litmus are known as. 

Neutral Solutions : These solutions are neither acidic nor basic in nature.

(B) saponification

Sulphuric acid < car battery acid < washing up liquid < milk of magnesia < metal polish < oven cleaner since:

Red : pH = 1

Pink : pH = 3-4

Yellow: pH = 5-6

Light blue : pH = 9

Dark blue : pH = 10

Purple: pH = 11

(a) Milk is made slightly alkaline so that it may not become sour easily due to the formation of lactic acid in it.

(b) The alkaline milk takes a longer time to set into curd because the lactic acid being formed has to first neutralise the alkali present in it.

Analgin is an analgesic

Phenolphthalein is one of the chemical indicator. If solution is acidic the phenolphthalein is colourless, when the solution is basic it gives pink colour.

The correct answer is (iii) Sn⁴⁺

The taste will be slightly sour as it is weakly acidic.

It will turn red litmus blue as it is basic in nature.

1. Sour taste substances turn blue litmus to red. 

2. Bitter taste substances turn red litmus to blue. By these tests we can test them as acids and bases.

i) bitter, soapy (slippery) to touch 

ii) electricity, electrolytes 

iii) acids, water 

iv) pink

Since the pH of a sample of vegetable soup is 6.5. So according to pH paper, it is acidic in nature. And acids are sour in taste. So vegetable soup will be sour in taste.

a) The summer sun was very hot and the street seemed to be on fire. The heat was intense.

b) It rained heavily all of a sudden. The rainwater from the rooftop had to come out through the drainage pipe. Water gushed out of the pipe and struggled out throwing the dust and garbage from the rooftop and in the pipe.

The gas that extinguishes a burning candle is carbon dioxide. It is formed by the action of dilute hydrochloric acid on a metal carbonate or metal hydrogen carbonate and produces effervescence. Since one of the compounds formed is calcium chloride, this shows that the metal compound is calcium carbonate. It cannot be calcium hydrogen carbonate because calcium hydrogen carbonate is found in solution.
Thus, the metal compound A is calcium carbonate (CaCO₃). Calcium carbonate reacts with dilute hydrochloric acid to form calcium chloride, carbon dioxide and water.
CaCO₃(s) + 2HCl(aq) ----> CaCl₂(aq) + CO₂(S) + H₂O(l)

Substance X is sodium hydrogen carbonate; Gas Y is carbon dioxide.

NaHCO₃(S) + HCl(aq) → CO₂ (g) + NaCl (aq) + H₂O (l)

 The answer is (a) less than 7

The PH is acidic to below 7 to ensure easy breakdown of food particles. PH of stomach juices is usually 3.

When a solution of an acid is diluted, the concentration of hydronium ions (H₃O⁺) per unit volume decreases.

(i) X- Sodium hydrogen carbonate or baking soda.

Y-CO₂

(ii) NaHCO₃+HCl → NaCl+H₂O+CO₂↑

1 M HCl solution have a higher concentration of H⁺ ions than 1 M CH₃COOH solution because HCl is a strong acid than CH₃COOH. Hence the H in HCl is able to dissociate very quickly from its formula unit mass and gets liberated in the form of H⁺ very quickly leading to a rapid increase in the H+ concentration but CH₃COOH is a weak acid and the H present in it is not able to dissociate quickly and completely from its formula unit mass in the form of H⁺ ions which leads to a slow increase in the H+ ion concentration and a low concentration of H⁺ ions in the solution.

On diluting an acid,the concentration of hydronium ions (H₃O⁺) in it decreases.

(i) Ammonium chloride, NH₄Cl

(ii) Sodium carbonate, Na₂CO₃

(iii) Sodium chloride, NaCl

(a) Solution of glucose will not conduct electricity because it does not have ions.

(b) Dil. HCl will conduct electricity because of it produces H⁺ ions in water.

(i) Bee-sting injects methanoic acid.

(ii) A mild base like baking soda will give relief.

(i) Acidic-SolutionA 

Basic-Solution B

(ii) Solution A because H⁺ ion concentration is higher in acidic solutions.

(a) (i) Single bond: Methane, CH₄ . They are quite unreactive hence they undergo substitution reaction with chlorine in presence of sunlight.

(ii) Double bond: Ethene, CH₂ =CH₂ . They undergo addition reaction in the presence of a catalyst like nickel or palladium.

(b) A detergent is the sodium salt of long chain benzene sulphonic acid which has cleansing properties in water. Ex: Sodium n-dodecyl benzene sulphonate.

(c) Detergents are better cleansing agents than soaps because they do not form insoluble calcium and magnesium salts with hard water, and hence can be used for washing even with hard water.

1. Boiling points increases regularly as the molecular mass increases due to a corresponding increase in their Van der waal’s force of attraction. Among isomeric alcohols 2° – alcohols have lower boiling points than 1° – alcohols due to a corresponding decreases in the extent of H-bonding because of steric hindrance. Thus the boiling point of Butan – 2 – ol is lower than that of Butan – 1 – ol. Overall increasing order of boiling points is, 2 – methylpropan – 2 – ol < Butan – 2 – ol < Butan – 1 – ol

2. 2°-alcohols have lower boiling points than 1° – alcohols due to a corresponding decrease in the extent of H – bonding because of steric hindrance. Therefore Propan – 1 – ol has higher boiling point than Propan – 2 – ol. Hydrogen group increases, boiling point also increases. Overall increasing order of boiling points is, propan – 2 – ol < Propan – 1 – ol < propan – 1, 3 – diol < propan -1, 2, 3 – triol

When the same concentration of HCI and acetic acid are taken (one molar), then these produce different amounts of H⁺ ion (as HCI dissociates completely). HCl gives more H⁺ but acetic acid gives less H⁺ ions (as this does not dissociate completely).

Acid rain is a by-product of a variety of human activities which release oxides of sulphur and nitrogen in the atmosphere. Burning of fossil fuels, coal, oil, petrol and diesel produces sulphur  dioxide and nitrogen oxide which pollute the air. Polluted air also contains many oxidising agents which produce oxygen because of excessive heat. This oxygen combines with the oxides of sulphur and nitrogen and rain water to form acids.

2SO₂ + O₂ + 2H₂O → 2H₂SO₄

4NO₂ + O₂ + 2H₂O → 4HNO₃

Hydrochloric acid will be a stronger acid because it produces more H⁺ ions.

HCI is stronger because it gives rise to more H⁺ ions than acetic acid.

(B) CH₃C = CH + NaOCH₃ → HC = CNa + CH₃OH