A student mixed some soil with water in a beaker and allowed it to settle. He filtered the contents of the beaker and obtained a clear filtrate. When he put a few drops of the filtrate on the pH paper, the pH paper turned yellowish orange. Which of the following should the student put on this pH paper so that it may change its colour to greenish-blue?
(1) NaHCO₃ solution
(2) HCI solution
(3) Vinegar solution
(4) Common salt solution

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Solution

The yellowish orange colour of the pH paper indicates it is an acid. So, to covert it to greenish blue we have to add a base in it. From the given options, sodium bicarbonate is a base which will again convert the colour of pH paper to greenish blue.

Hence, the correct answer is option 1.

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The yellowish orange colour of the pH paper indicates it is an acid. So, to covert it to greenish blue we have to add a base in it. From the given options, sodium bicarbonate is a base which will again convert the colour of pH paper to greenish blue. Hence, the correct answer is option 1.

The yellowish orange colour of the pH paper indicates it is an acid. So, to covert it to greenish blue we have to add a base in it. From the given options, sodium bicarbonate is a base which will again convert the colour of pH paper to greenish blue.

Hence, the correct answer is option 1.