Acids, Bases And Salts

Adding water to acids release energy. We can experience it by touching at test tube (it becomes hot), sometimes the heat is too large to handle and glasses of container or test tube may explode and acid can spill over. So we always take water in excess and drop acid drop by drop, so that heat produced can be cooled down by this water and accidents can be prevented.

Adding water to acids release energy. We can experience it by touching at test tube (it becomes hot), sometimes the heat is too large to handle and glasses of container or test tube may explode and acid can spill over. So we always take water in excess and drop acid drop by drop, so that heat produced can be cooled down by this water and accidents can be prevented.

Acids and bases cancel each other’s properties and make salt and water as product.

turmeric is natural indicator and change its color to red in presence of base. You might have seen any spot of turmeric on white clothes being turned to red when washed with soaps. This is because soaps are basic in nature.

Turmeric Turns Red with Soap Solution (Base)

phenolphthalein is artificial indicator that turns into pink in basic environment.

Quick lime, slacked lime and calamine all are basic in nature. They will make soil more basic if added and quality of soil will decrease.

litmus is extracted from lichens algae.

Litmus Paper and Lichens Algae

Chemical changes are those which brings the change in chemical composition of any substance. After neutralization acids and bases are no longer in reaction mixture, they get completely transformed to salt and water. Also all chemical changes are irreversible in nature.

Turmeric is natural indicator which changes its color from yellow to red in basic environment.

Curd and vinegar both are sour in nature and hence are acidic. Curd contains lactic acid while vinegar contains acetic acid.

Phenolphthalein changes its color to pink in case of basic solution and remains colorless in acidic and neutral solutions.

Turmeric is natural indicator which turns its color from yellow to red in basic solutions.

Yes we can get solid sodium chloride by separating water from it. One simple method is to heat up the solution to 100֯ C so that whole water gets evaporated and we get salt as remnant.

(a) False

Substances are classified into three categories. Those which are not acidic or basic comes under category of neutral substances.

(b) False

The fact given is not necessary. It actually depends on the nature of indicator. For example: phenolphthalein gives colourless mixture with acids.

(c) True

Lime water is basic in nature and hence turns red litmus to blue.

(d) False

The mixture of common salt with water is neutral and does not change color of litmus.

(e) False

Phenolphthalein is human made or artificial indicator.

(f) True

Reason: Calamine is basic in nature. Ant sting release methanoic acid in the sting area which creates irritation. Calamine being a base can undergo neutralization reaction with this acid to destroy its effect.

(g) False

Lemon water tastes sour and hence it is acidic in nature.

No! She should not take orange juice in case of acidity. During acidity, the amount of hydrochloric acid present in our stomach (for digestion of food) rises. Giving orange juice which itself is sour and hence acidic (contains citric acid) will increase amount of acid more and worsen the condition. Instead she should be given basic substances like Milk of Magnesia for treatment.

Neutral substance do not change the color of any type of litmus paper.(Test tube A and D)

Acidic substances changes colour of Blue litmus to red.(test tube C)

Basic substances changes color of red litmus to blue( test tube B).

Baking soda is a better remedy than lemon juice.

Wasp sting releases methanoic acid into the sting area which causes irritation. Baking soda is basic in nature and hence can undergo neutralization reaction with this acid to trigger its ill effects.

The effect of ant bite can be neutralized by rubbing moist baking soda on the affected area.

Column II contains the things which we see in our daily life. We need to match them appropriately with correct acid or base which is present in them. Book gives info about all things in column II

(a) Lemon juice and vinegar taste sour because they contain Acids .

Acids taste sour.

(b) Turmeric and litmus are Natural acid-base indicators.

Information given in book.

(c) Phenolphthalein gives Pink colour with lime water.

Phenolphthalein gives pink color with basic substances and lime water is basic in nature.

(d) When an acidic solution is mixed with a basic solution, they Neutralise each other forming Salt and water.

Acids and bases react to perform neutralization reaction which gives salt and water as product.

A solution of china rose turns green in a basic solution, and bright pink or magenta in an acidic solution. Since after addition of solution ‘A’ by Boojho, the testube solution became dark pink, hence we can conclude that it contained basic solution. Similarly, Paheli’s Solution ‘B’ contains acid because it turns china rose green. Since no color change was observed using Solution ‘c’ it is neutral.

So Solution A = Base

Solution B= Acid and Solution C= neutral.

(1) It is used to test whether a substance is acidic or basic.: INDICATOR

(2) The solution which does not change the colour of either red or blue litmus.: NEUTRAL

(3) It is a natural indicator and gives pink colour in basic solution. : TURMERIC

(4) Phenolphthalein gives pink colour in this type of solution. : BASE

(5) Nature of ant’s sting. : ACIDIC

(6) It is responsible for increase in temperature during a neutralisation reaction.: HEAT

(7) Colour of blue litmus in lemon juice. : RED

Information related question. All definitions given in book.

The farmer has to first make sure whether the soil is acidic or basic. For this he has to take the sample of his soil to laboratory and get it tested.

If the soil is Acidic, we will have to add some basic substance like Dry lime, or limestones so that they neutralize the excess acid of the soil.

If the soil is Basic, we will have to add acidic substances to neutralize its effects. Generally organic substances are added in the soil in this case because they generate acids on decomposition.

We can taste and tell which one of the solution is acidic and which one is basic.

For sugar solution and salt solution: Taste will be sweet and salty. and we can hence conclude their taste is not sour or bitter. So, they come in category of neutral substances.

For Tamarind solution the taste will be sour, hence we can conclude it is acidic in nature.

For Baking soda solution, the taste will be bitter, hence we can conclude it is basic in nature.

(a) Test tube A : Color change to RED

Test tube B: No color Change

Test tube C: No color Change

(b) Test tube A: No Color Change

Test tube B: Color change to Blue

Test tube C: No change

(c) Test tube A: Colourless solution

Test tube B: Pink solution

Test tube C: Colorless solution

Tartaric acid(Solution A) is acidic in nature. Soap (solution B)is basic in nature. Pure water (Solution C ) is neutral in nature.

Acid turns blue litmus red, base turns red litmus blue, neutral substances do not change the color of litmus. Phenolphthalein gives pink color with base and colorless solution with acid and neutral substances.

(a) Factory wastes are generally highly acidic or basic chemicals. They make life of aquatic animals like fish difficult. Functions like digestion, respiration etc. are carried out by living organisms only in normal conditions which is neither too acidic or basic. Hence fish are dying.

(b) Bases neutralize and destroy the acids. Hence, we can add any base like dry lime, Limestones etc. in the waste to make it neutral and less harmful.

Following are the neutralization reactions related in daily life situations:

1) Acidity:

Acidity is caused when hydrochloric acid, which is present in our stomach to digest food items, gets produced in excess amounts and give burning sensation. This can be treated by intake of basic substances like baking soda or Milk of Magnesia.

2)Ant-sting:

Ant sting releases formic or methanoic acid in the body which causes irritation. It can be treated by rubbing moist baking soda which is basic in nature.