Q1 of 13 Page 106

Organic acids are present in a number of substances we use. (e.g. Tomato, orange, apple, grapes, curd etc.)

Identify the organic acids in each of them and prepare a list.

Number of acids are present in the fruits/vegetables and other eatables that we use. Such sources are listed below with the acids associated with them:


More from this chapter

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6

Some salts are given in column A. Their chemical formulae and uses are given in column B and column C irregularly. Match the columns by identifying the correct chemical formulae and the uses of the salts.

 7

The pH values of some substances are given in the table. Analyse the table and answer the questions that follow.


a. Is blood acidic or alkaline in nature?


b. The pH value of pure milk is 6.4. Does the pH value increase or decrease when milk changes to curd? Justify your answer.


c. Among the substances given in the table,


i) Which one is strongly alkaline?


ii) Which one has weak acidic nature?

 2

Haven’t you identified the pH value of the soil in relation with different crops? Identify the pH value of soil samples collected from different places.

Identify the crop that is suitable for the soil of each area on the basis of its pH value.

 3

Complete the chemical equations for the ionisation of phosphoric acid.

H3PO4→ H+ + H2PO4–


(Dihydrogen phosphate ion)


H2PO4–→ H+ + .....................


(Hydrogen phosphate ion)


......... → H+ + PO43–


(Phosphate ion)