You are provided with a sample and a strip of red litmus paper. How wo...
Confirmation of the Nature of the Sample using Red Litmus Paper
To confirm the nature of the sample provided, we can perform a simple test using red litmus paper. Red litmus paper is commonly used to determine whether a substance is acidic or neutral. Here's how we can confirm the nature of the sample using red litmus paper:
Step 1: Obtain a strip of red litmus paper
Start by obtaining a strip of red litmus paper. Ensure that the paper is clean and dry before using it for the test.
Step 2: Dip the litmus paper in a dilute solution of NaOH
Dip the red litmus paper into a dilute solution of sodium hydroxide (NaOH). Sodium hydroxide is a strong base and its solution is commonly used to determine whether a substance is acidic or not.
Step 3: Place 2 drops of the liquid sample on the litmus paper
After dipping the litmus paper in the NaOH solution, place 2 drops of the liquid sample on the paper. Ensure that the drops are evenly distributed on the paper.
Step 4: Observe the color change
Observe the color change of the red litmus paper after the liquid sample is added. If the litmus paper turns blue or purple, it indicates that the sample is acidic. This is because the red litmus paper is sensitive to acidic substances and changes color in their presence.
Explanation of the answer (Option B)
In this question, the correct answer is option B, which involves dipping the litmus paper in a dilute solution of NaOH and then placing 2 drops of the liquid sample on it. This method helps in determining the acidic nature of the sample.
By using a dilute solution of NaOH, we create a basic environment which can neutralize any acidity in the sample. If the sample is acidic, the red litmus paper will turn blue or purple, indicating the presence of acid. However, if the litmus paper remains red, it means that the sample is not acidic.
Other options mentioned in the question, such as dipping the litmus paper in the sample itself (Option A), or using a dilute solution of NaCl (Option C), or placing four drops of the liquid sample on the litmus paper (Option D), may not provide accurate results or may not be suitable for determining the nature of the sample. Therefore, option B is the most appropriate choice for confirming the acidic nature of the sample using red litmus paper.
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