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Experiments on Digestion

Given below a...

Question

Given below are the steps to test the presence of proteins in a food item.

(i) Take a small quantity of the food item in a test tube, add 10 drops of water to it and shake it.

(ii) Make a paste or powder of food to be tested.

(iii) Add 10 drops of caustic soda solution to the test tube and shake well.

(iv) Add 2 drops of copper sulphate solution to it.

Which of the following is the correct sequence of steps?

(a) i, ii, iv, iii

(b) ii, i, iv, iii

(c) ii, i, iii, iv

(d) iv, ii, i, iii

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Solution

The answer is (b).

The presence of proteins in a food material is tested on the basis of a reaction between proteins and alkaline solution of copper sulphate, that gives a violet colour. The test involves the following steps in sequences - ii $\to$ i $\to$ iv $\to$ iii , that is

(ii) Make a paste or powder of food to be tested.

(i) Take a small quantity of the food item in a test tube, add 10 drops of water to it and shake it.

(iv) Add 2 drops of copper sulphate solution to it.

(iii) Add 10 drops of caustic soda solution to the test tube and shake well.

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Q. Question 1
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Question 4

Read the food items given below.

(i) Wheat

(ii) Ghee

(iii) Iodised salt

(iv) Spinach

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(b) (ii) and (iv)

(c) (i) and (ii)

(d) (iii) and (iv)

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Experiments on Digestion

Standard IX Biology

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