Practice Questions

Identify the acid found in sour milk (curd) and in an ant sting.

Name two natural indicators and one synthetic indicator used to test for acids and bases.

Define a neutralization reaction and write the general word equation for it.

What is the chemical name and formula for washing soda?

Justify the classification of non-metallic oxides (e.g., $CO_2$) as acidic oxides using a general reaction with a base.

If $10$ mL of a hydrochloric acid solution completely neutralizes $20$ mL of a given sodium hydroxide solution, calculate the volume of the same hydrochloric acid solution that would be required to neutralize $50$ mL of the same sodium hydroxide solution.

Justify why applying a paste of baking soda ($NaHCO_3$) on a bee sting provides relief.

A farmer finds the soil pH in his field is 4.5. Apply your knowledge of neutralization to suggest a chemical substance he could add to the soil to make it suitable for growing crops.

A white cloth has a yellow curry stain. Apply your knowledge of natural indicators to explain why the stain turns reddish-brown when soap is applied to it.

Name the gas that is liberated when an acid reacts with a metal. How is its presence tested?

Critique the traditional practice of storing curd or other sour food items in brass or copper vessels.

Evaluate the industrial significance of the chlor-alkali process. Justify your evaluation by proposing one important use for each of its three products: sodium hydroxide, chlorine, and hydrogen gas.

Explain why an aqueous solution of an acid conducts electricity.

Explain the role of pH in our digestive system and how antacids provide relief from indigestion.

List two uses of baking soda (sodium hydrogencarbonate) and two uses of washing soda (sodium carbonate).

A student tests three unknown solutions P, Q, and R with universal indicator. P turns red (approximate pH 1), Q turns blue (approximate pH 9), and R turns green (approximate pH 7). Analyze these results to classify each solution and arrange them in increasing order of their hydrogen ion ($H^+$) concentration.

A student has two solutions, A with pH 2 and B with pH 5. Evaluate which solution is more acidic and by what factor the concentration of hydronium ions ($H_3O^+$) differs between them. Justify your reasoning.

Explain the concept of the pH scale. What do the values pH < 7, pH = 7, and pH > 7 indicate about a solution?

Define 'water of crystallization' and give an example of a salt that contains it, including its chemical formula.

Recall the chemical formula for gypsum and explain how it is related to Plaster of Paris.

Describe why it is recommended to add acid to water, and not water to acid, while diluting a concentrated acid.

Compare the reaction of zinc granules with equal concentrations of hydrochloric acid ($HCl$) and acetic acid ($CH_3COOH$). Analyze why a difference in the rate of gas evolution is observed.

Analyze the products formed during the chlor-alkali process. Demonstrate with a balanced chemical equation and explain why the process is named so. List one use for each of the three main products.

Contrast the effect of passing dry $HCl$ gas over dry blue litmus paper versus bubbling the gas through water and then testing with blue litmus paper. Analyze the reason for any difference in observation.

A farmer finds the soil in his field has a pH of 4.8. Propose a suitable chemical treatment to improve the soil quality for most crops. Justify your choice with a relevant chemical equation.

A student claims that since both glucose ($C_6H_{12}O_6$) and hydrochloric acid ($HCl$) contain hydrogen, they should both behave as acids. Critique this statement and propose an experiment to prove your point.

Formulate a two-step laboratory procedure to prepare washing soda ($Na_2CO_3 \cdot 10H_2O$) starting from common salt ($NaCl$). Write balanced chemical equations for the reactions involved.

Examine the chemical formula for Plaster of Paris, $CaSO_4 \cdot \frac{1}{2}H_2O$. What does the half molecule of water signify in this formula unit?

Apply the concept of electrical conductivity to demonstrate how you would distinguish between solutions of glucose ($C_6H_{12}O_6$) and hydrochloric acid ($HCl$). Analyze the underlying reason for the difference in conductivity.

Demonstrate the process of neutralization by explaining what happens at the molecular level when sodium hydroxide ($NaOH$) solution is added dropwise to hydrochloric acid ($HCl$) solution containing phenolphthalein indicator. Include the overall and ionic equations for the reaction.

Analyze the process of diluting a concentrated acid like $H_2SO_4$. Explain why it is recommended to add acid slowly to water and not water to acid, relating your answer to the energy change involved.

Evaluate the statement: 'The process of diluting a concentrated acid by adding water to the acid is just as safe as adding acid to water.' Justify your evaluation.

List the products formed when a metal carbonate reacts with an acid. Provide the general word equation for this type of reaction.

A baker wants to make a cake rise. Evaluate the choice between using only baking soda ($NaHCO_3$) and using baking powder. Propose which is the better choice for a standard cake recipe and justify why.

Formulate a balanced chemical equation for the reaction that occurs when excess carbon dioxide is passed through limewater. Justify why the white precipitate that initially forms later disappears.

Propose a chemical reason for storing Plaster of Paris ($CaSO_4 \cdot \frac{1}{2}H_2O$) in a moisture-proof container.

Summarize the reason why dry HCl gas does not change the color of dry litmus paper, but HCl solution does.

Design an experiment to compare the strengths of two weak acids, acetic acid ($CH_3COOH$) and carbonic acid ($H_2CO_3$), using a universal indicator and a pH meter. Justify your methodology and predict the expected observations.

A metal compound 'X' reacts with dilute $H_2SO_4$ to produce a brisk effervescence. The gas evolved turns limewater milky. Analyze this information to identify compound 'X' and the gas evolved. Write balanced chemical equations for the reaction of 'X' with $H_2SO_4$ and the reaction of the evolved gas with limewater, assuming 'X' is a calcium compound.

Design a simple, functional model of a soda-acid fire extinguisher. Create a labeled diagram and formulate the chemical equation for the reaction that powers it.

You are provided with three unlabelled test tubes containing aqueous solutions of sodium acetate ($CH_3COONa$), ammonium chloride ($NH_4Cl$), and sodium chloride ($NaCl$). Design a simple experimental procedure using only red and blue litmus papers to identify the contents of each test tube. Justify the expected observations.

Analyze why baking powder, which is a mixture of baking soda and a mild acid like tartaric acid, is preferred over using only baking soda ($NaHCO_3$) for making cakes.

Describe the chlor-alkali process. Name the three main products and list one use for each.

Compare and contrast the properties and uses of washing soda ($Na_2CO_3 \cdot 10H_2O$) and baking soda ($NaHCO_3$). Include their chemical names, their nature, their reaction on heating, and one distinct use for each.

Compare the pH of a salt formed from a strong acid and a strong base (e.g., $NaCl$) with a salt formed from a strong base and a weak acid (e.g., $CH_3COONa$). Justify your comparison.