Acid and alkali

Post on 22-Oct-2014

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To study on Acid and Alkali

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Acids have a sour taste. They are corrosive.

An Acid is a sour tasting liquid and highly corrosive and turns into litmus red.

Acids

There are many acids present in our everyday lives.

Lemon juice contains citric acid, and vinegar contains ethanoic acid.Some strong acids are hydrochloric acid, sulphuric acid and nitric acid. Some weak acids are cid, citric acid and carbonic acid.

Why are acid Why are acid dangerous ?dangerous ?

Certain chemical properties make an acid dangerous. Certain chemical properties make an acid dangerous. For e.g., sulphuric acid has the property of absorbing For e.g., sulphuric acid has the property of absorbing water. Thus when it spills on the body, it can cause water. Thus when it spills on the body, it can cause severe burns. Nitric acid similarly is an oxidizing agent. severe burns. Nitric acid similarly is an oxidizing agent. It reacts violently with the skin, muscles and bones to It reacts violently with the skin, muscles and bones to cause lethal damage. cause lethal damage.

Alkalis

An alkaline solution is a mixture of base solids dissolved in water.

Alkalis react with acids and neutralise them.

Everyday we use alkalis unknowingly. They are slippery. They are corrosive.

Why are alkalis dangerous ?

Alkalis are dangerous . They should be given proper care. Even they have chances to burn our skin. And even the diluted sodium hydroxide solution can burn our skin.

Neutralisation

When acid and alkali react , a process

called neutralization occurs in which a salt and water is formed.

Indicators

They change colour in acid or alkaline solutions. Different indicators change to different colours.

Indicators help you find out whether a solution is acidic or not.

LitmusTest

Litmus is an indicator. It changes colour in acid and alkaline solutions.

Litmus is red in an acid. Litmus is blue in an alkali.

Universal Indicator Universal indicator changes colour in acids

and alkalis.

Its colour shows the strength of an acid or alkali.

The pH scale

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Applications of Neutralisation

• Curing Indigestion: When a tablet of sodium bicarbonate is swallowed the chemical dissolves to make an alkaline solution,which neutralises the acid in the stomach and cures the indigestion.

• Insect Stings Bee stings is acidic and may be neutralized by soap,which is an alkali . A wasp sting is alkaline an may be neutralized with vinegar , which is a weak acid.

Rainfall made sufficiently acidic by atmospheric pollution that it causes environmental harm, typically to forests and lakes.

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When acid rain reaches the ground,it drain into the soil,disssolves some of the minerals there and carries them away.This process is called leaching.

It help the plant the not get proper food and growth.It help the plant the not get proper food and growth.

It drains into rivers and lakes and lower the pH of the water.

Many forms of water life are sensitive to pH of water and cannot survive if it is too acidic.

If they are concentrated the can also damage our skin.

They also damage the famous building like tajmahal.