Explore topic-wise InterviewSolutions in Current Affairs.

The indicator helps us to find whether the solution is acidic or basic or neutral.

Blue litmus: Litmus, an organic dye usually used in the laboratory as an indicator of acidity or alkalinity. Naturally pink in colour, it turns blue in alkali solution.

1. The substance that turns blue litmus to red is acidic in nature. 

2. The substance that is soapy to touch and turns red litmus to blue is basic in nature. 

3. If the substance given did not change the colour of either blue or red litmus, then it is said to be neutral in nature.

Some substances change their taste when cooked.

Salts that change red litmus to blue are basic salts.

Without sugar lemon juice will be sour to taste.

Neutral substance: A neutral substance is a material that exhibits neither Acid nor a Base property and does not change the colour of litmus paper.

Basic substances: The substances which are soapy to touch are basic in nature. 

Ex: soap, glass cleaner, etc.

Acidic substances: The substances that contain different acids and the ability to turn blue litmus red. 

Ex: lemon – citric acid, banana – ascorbic acid etc.

Yes. Some substances change colour when added to other substances.

Salts: A chemical compound formed by replacing all or part of the hydrogen ions of an acid with metal ions or electropositive radicals.

Sodium hydroxide is a alkali

Caustic soda: A strongly alkaline caustic soda used in manufacturing soap and paper and aluminium and various sodium compounds.

Neutralization: A reaction between an acid and a base that yields salt and water.

Acid rain: Rain that contains a high concentration of pollutants, chiefly sulphur dioxide and nitrogen oxide, released into the atmosphere by the burning of fossil fuels such as coal or oil.

Correct option is B) H₂

Fire extinguisher: A portable apparatus containing chemicals that can be discharged in a rapid stream to extinguish a small fire.

1. b 

2. c 

3. d 

4. a

Neutralisation reaction.

Lactic acid.

Correct option is A) H₂

Phenolphthalein is pink in basic solution.

Methyl orange, Phenolphthalein.

Apart from natural acids, there are certain acids like Hydrochloric acid, Sulphuric acid and Nitric acid etc., that are prepared from minerals.

Turmeric and Litmus.

Correct option is C) Turmeric & rose petals

Option C is correct

1. When I have touched soap water and lime water, they are soapy to touch. 

2. These substances are basic in nature.

Correct Answer is: A. Sulphide

Sulphide ores are concentrated by froth- flotation process. Only sulphide ores are concentrated by this method because pine oil selectively wets the sulphide ore and hence brings it to the froth.

The Correct option is A. Sulphide

Correct option is (d) descriptive and predictive

Correct Answer is: (B) Decreases on dilution 

For strong electrolytes λ_m increases slowly with dilution but for weak electrolytes λm increases steeply on dilution.Molar conductivity increases with decrease in concentration because both the number of ions as well as the mobility of increase with dilution.

Correct option is A) Grape juice

Correct Answer is: (A) Irreversible in nature 

Chemisorption is irreversible process while physical adsorption is reversible in nature. Chemisorption is an adsorption where the forces involved are valence forces of the same kind as those operating in the formation of chemical compounds. Thus, Chemisorption leads to formation of the so called a "surface compound".

PCl₄^-, because P has 10 electrons which cannot be accommodated in sp³ hybrid orbitals.

1. The youngest son borrowed an unused plot of land. [2] 

2. The crop grew well and yielded twenty-five sacks of rice. [4] 

3. The sack was lying with the youngest son for a long time. [1] 

4. Sowed the rice. [3]

grew – simple past tense

The youngest brother confessed that since the sack of rice was lying with him for a long time, he sowed it in the unused plot of land. He added that fortunately the crop had grown well and yielded twenty-five sacks of rice. He had kept five of the sacks and sold the rest.

There was a lot of hard work, effort and money involved in sowing the seeds and harvesting the crop. The youngest brother was therefore justified in asking for a share in the money.

The middle brother distributed the rice among the poor in the name of the businessman.

The businessman was getting old. He was looking for a son-in-law who would not only be a good husband to his daughter but also would handle his business well.

The eldest brother was worried that it would get spoilt so he sold it to his customers.

Perfect correlation is that when changes in two related variables are exactly proportional It is of two types.

1. Positive perfect correlation and

2. Negative perfect correlation

There is perfect positive correlation between the two variables if equal proportional changes are the same direction. It is expressed as +1. If equal proportional changes are in the reverse direction then there is negative perfect correlation and it is described as -1.

a.  Example of positive perfect correlation

b. Example of perfect negative correlation

Range is the difference between the highest value and lowest value in a series.

Quartile deviation is half of Inter quartile Range. Quartile Deviation \(\frac{Q_3-Q_1}{2}\)

1. Simple correlation: When the relationship between two variables is studied and if these are is dependent then such correlation is called simple correlation.

For example relationship between income and expenditure.

2. Partial correlation: When more than two variables are involved and out of these the relationship between two variables is studied only treating other variables as constant, then such correlation is partial.

1.  r as 1 means that it is perfect positive relationship between two variables.

2.  r as -1 means that there is perfect negative relationship between two variables.

3.  r as O means that there is Lack of correlation between two variables.

Mean deviation is the arithmetic average of the deviation of all the values taken from some average value (mean, median, mode) of the series, ignoring sign (+or-) of the deviations.

No, but there is possibility o independence.

Impartiality is secular is unbeauty, honesty, Patritism etc -are some variable where accurate measurement is difficult.