acids,bases in lab

Question 1

What are the solutions collected from the science laboratory?

Answer 1

Hydrochloric acid (HCl), sulphuric acid (H2SO4), nitric acid (HNO3), acetic acid (CH3COOH), sodium hydroxide (NaOH), calcium hydroxide [Ca(OH)2], potassium hydroxide (KOH), magnesium hydroxide [Mg(OH)2], ammonium hydroxide (NH4OH)

These solutions are commonly used in laboratory experiments to study acid-base reactions.

Question 2

What indicators are used to test the solutions in Activity 2.1?

Answer 2

Red litmus, blue litmus, phenolphthalein, and methyl orange solutions

These indicators help determine whether a solution is acidic or basic based on color change.

Question 3

What is the purpose of using indicators in acid-base testing?

Answer 3

To determine whether a substance is acidic or basic by change in colour

Indicators provide visual cues of the pH level of a solution.

Question 4

What are olfactory indicators?

Answer 4

Substances whose odour changes in acidic or basic media

Examples include onions, vanilla, and clove oil.

Question 5

What is the first step in Activity 2.2 for testing olfactory indicators?

Answer 5

Take some finely chopped onions in a plastic bag along with some strips of clean cloth

This step prepares the olfactory indicators for testing.

Question 6

What should be done after rinsing the cloth strips with water in Activity 2.2?

Answer 6

Check their odour again

This helps to observe any changes in odour after exposure to acids or bases.

Question 7

What solutions are used to test the odour changes of the cloth strips?

Answer 7

Dilute HCl solution and dilute NaOH solution

These solutions are used to observe the effect of acids and bases on the olfactory indicators.

Question 8

What should be added to the test tubes containing dilute HCl and NaOH to check for odour changes?

Answer 8

A few drops of dilute vanilla essence

This tests the effect of acids and bases on the odour of the vanilla essence.

Question 9

Fill in the blank: The cloth strips can be used to test for acids and bases after being left overnight in the _______.

Answer 9

fridge

Question 10

Which substances were tested as olfactory indicators based on observations?

Answer 10

Vanilla, onion, and clove

The ability of these substances to change odour in acidic or basic media was evaluated.

Question 11

True or False: Methyl orange is an indicator used to test for acidic and basic solutions.

Answer 11

True

Question 12

What changes are observed when testing solutions with indicators?

Answer 12

Change in colour

The specific colour change indicates whether the solution is acidic or basic.