Question

D. Answer in one or two sentences.

1. Write down the uses of acids.

2. What are antacids? Give some examples.

3. What do you understand by neutralisation?

4. What are indicators? Name some indicators and their effects on acids and bases.

5. Differentiate between acids and bases.

6. How does a salt react with (a) an acid (b) a base?

7. How will you identify whether a substance is an acid or a base? (i) By using litmus paper (ii) At home, if you don't have a litmus paper.

8. How does a farmer maintain the balance of acidic character of soil?​

Answer 1

Answer:

Acids are used as catalysts in industrial and organic chemistry; for example, sulfuric acid is used in very large quantities in the alkylation process to produce gasoline. Some acids, such as sulfuric, phosphoric, and hydrochloric acids, also effect dehydration and condensation reactions.

An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion or an upset stomach. Some antacids have been used in the treatment of constipation and diarrhea. Currently marketed antacids contain salts of aluminum, calcium, magnesium, or sodium.Examples of antacids include:

Aluminum hydroxide gel (Alternagel, Amphojel)

Calcium carbonate (Alka-Seltzer, Tums)

Magnesium hydroxide (Milk of Magnesia)

Gaviscon, Gelusil, Maalox, Mylanta, Rolaids.

Pepto-Bismol.

The products formed on mixing an acid and a base are salt and water. The reaction in which an acid reacts with a base to form salt and water is called neutralisation.

An indicator is a 'dye' that changes colour when it is put into an acid or a base. An indicator gives different colours in acid and base. A substance which contains an acid is said to be acidic whereas the substance which contains a base is said to be basic.Acid-base indicators are chemicals used to determine whether an aqueous solution is acidic, neutral, or alkaline. Because acidity and alkalinity relate to pH, they may also be known as pH indicators. Examples of acid-base indicators include litmus paper, phenolphthalein, and red cabbage juice.

Acid is a kind of chemical compound that when dissolved in water gives a solution with H+ ion activity more than purified water. A base is an aqueous substance that donates electrons, accept protons or release hydroxide (OH-) ions. An acid is a proton donor. While a base is a proton acceptor.

acid + hydrogencarbonate → salt + water + carbon dioxide

Observations: solid white sodium hydrogencarbonate disappears, colourless solution produced, bubbles. The carbon dioxide gas produced in these reactions can be tested.

BY USING LITMUS PAPER

Well-decomposed compost helps lower the pH of garden soil over time. Amending your soil each season with compost, which is rich in organic matter, is by far the best way to make your soil more acidic because it is done gradually and creates the most benefits for plant growth.

7th class 2nd lesson ACIDS AND BASES