Name ∞ Manpreet SinghClass ∞ 10th {G}Roll No ∞ 4Subject ∞ ScienceSubmitted To ∞ Mrs.Monika Gauri

Topic

Acids , Bases And Salts

Introduction

Acids and bases are known since the early development of chemistry. However, they are identified mainly on the basis of their observable properties such as taste or their effect on other substances.

Acids

Substances with sour taste are regarded as acids. Lemon juice, vinegar and grapes fruit juice etc. Sour taste due to the presence of different acids

Examples of Acid

Lemon Vinegar Grapes juice

Some common indicators with characteristics color

Indicators

litmus

phenolphthalein

Color in acidic

solution

red

colorless

Color in neutral

solution

purple

colorless

Color in basic solution

blue

pink

Methyl orange

red orange yellow

Uses of acids

1.Vinegar, used in the kitchen, is a liquid containing 3-6% acetic acid. It is used in pickles and in many food preparations.

2. Lemon and orange juice contains citric acid. Citric acid is used in the preparation of effervescent salts and as a food preservative.

3. Acids have been put to many uses in industry. Nitric acid and sulphuric acid are used in the manufacture of fertilizers, dyes, paints, drugs and explosives.

4. Sulphuric acid is used in batteries, which are used in cars, etc. Tannic acid is used in the manufacture of ink and leather.

5. Hydrochloric acid is used to make aqua region, which is used to dissolve noble metals such as gold and platinum.

6. Sulphuric acid is used in manufacturing fertilizers such as super phosphate, ammonium sulphate etc.

Properties of acids

Acids are typically sour to the taste, can change litmus paper red, will react with some medals to produce hydrogen and when added to bases will form salt and water.

Olfactory Indicators Olfactory indicators are the substances whose odour changes in acidic or basic medium . They are also known as the olfactory indicators . For eg. Onion and cloves

Bases Base is a substance that, in aqueous solution,

is slippery to the touch, tastes bitter, changes the color of indicators (e.g., turns red litmus paper blue), reacts with acids to form salts, and promotes certain chemical reactions (base catalysis). Examples of bases are the hydroxides of the alkali and alkaline earth metals (NaOH, Ca(OH)2, etc.). Such substances produce hydroxide ions (OH-) in aqueous solutions, and are thus classified as Arrhenius bases.

Examples of bases

Uses of bases1. Sodium hydroxide (caustic soda) is

used in the manufacture of soap. It is used in petroleum-refining; in making medicines, paper, pulp, etc. It is used in making rayon.

2. Ammonium hydroxide is used to remove ink spots from clothes and to remove grease from window-panes. It is used in the cosmetic industry.

3. Alkalis are used in alkaline batteries. Generally, potassium hydroxide is used in such batteries

4. Calcium hydroxide is also known as slaked lime. It is used to neutralize acid in water supplies; in the manufacture of bleaching powder; as a dressing material for acid burns; as an antidote for food poisoning; in the preparation of fungicides and in the mixture of whitewash. It is mixed with sand and water to make mortar which is used in the construction of buildings. It is also used by farmers on the fields to neutralize the harmful effects of acid rain.

Properties of bases

Bases provide OH- ions in solution; combine with H+; donate electrons for sharing with an electron-pair acceptor; proton acceptor. Chemically, bases raise the pH when added to a solution.

Salt

salts are ionic compounds that can result from the neutralization reaction of an acid and a base. They are composed of related numbers of cations (positively charged ions) and anions (negative ions) so that the product is electrically neutral (without a net charge). These component ions can be inorganic, such as chloride (Cl−), as well as organic, such as acetate (C2H3O2

−); and can be monatomic, such as fluoride (F−), as well as polyatomic, such as sulfate (SO4

2−).

S.NO Salt Commonname

Formula PositiveIon {cation}

NegativeIon {anion}

1 SodiumChloride

Table salt Nacl Na+ Cl-

2 copperSulphate

Blue vitriol CuSo4.5H2O Cu2+ SO42-

3 magnesiumCarbonate

Epsom salt MgSO4.7H2O

Mg2+ SO42-

4 CalciumCarbonate

Lime stone{marble}

CaCO3 Ca2+ CO32-

5 SodiumSuphate

Glauber’sSalt

Na2SO4.10H2O

Na+ SO42-

6 Zinc Carbonate

Calamine ZnCO3 Zn2+ CO32-

7 SodiumCarbonate

Washing Soda

Na2CO3.10H2O

Na+ CO32-

8 SodiumBicarbonate

Baking Soda

NaHCO3 Na+ HCO3-

9 Calcium sulphate hemihydrate

Plaster ofparis

CaSO4.½H2O

Ca2+ SO42-

Examples of salts

Uses of salt Boiling Water - Salt added to water makes the water boil

at a higher temperature, thus reducing cooking time (it does not make the water boil faster).

Peeling eggs - Eggs boiled in salted water peel more easily.

Poaching eggs - Poaching eggs over salted water helps set the egg whites.

Testing egg freshness - Place the egg in a cup of water to which two teaspoonfuls of salt has been added. A fresh egg sinks; a doubter will float.

Preventing browning - Apples, pears and potatoes dropped in cold, lightly salted water as they are peeled will retain their color.

Shelling pecans - Soaking pecans in salt water for several hours before shelling will make nut meats easier to remove.

Washing spinach - If spinach is washed in salted water, repeated cleanings will not be necessary.

Preventing sugaring - A little salt added to cake icings prevents them from sugaring.

Crisping salads - Salting salads immediately before serving will keep them crisp.

Improving boiled potatoes - Boiled potatoes will be given a fine, mealy texture by sprinkling with salt after draining, then returning them to the pan and shaking them back and forth quickly to get rid of the excess moisture.

Cleaning greasy pans - The greasiest iron pan will wash easily if you use a little salt in it and wipe with paper.

Cleaning stained cups - Rubbing with salt will remove stubborn tea or coffee stains from cups.

Cleaning ovens - Salt and cinnamon take the "burned food" odor away from ovens and stove burners. Sprinkle spills while oven and burners are still hot; when dry, remove the salted spots with a stiff brush or cloth.

Cleaning refrigerators - Use salt and soda water to clean and sweeten the inside of your refrigerator. It won't scratch enamel either.

Extinguishing grease fires - Salt tossed on a grease fire on the stove or in the oven will smother flames. Never use water; it will only spatter the burning grease.

Improving coffee - A pinch of salt in coffee will enhance the flavor and remove the bitterness of over-cooked coffee.

Improving poultry - To improve the flavor of poultry, rub the fowl inside and out with salt before roasting.

Removing pinfeathers - To remove pinfeathers easily from a chicken, rub the chicken skin with salt first.

Cleaning tarnished silverware - Rub tarnish with salt before washing.

Properties of salts

1.soluble in water 2.salt solutions are highly conductive 3.salts have a high melting point

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