Question 1: Define the pH scale and explain what it measures in a solution.

Answer: The pH scale is a numerical scale ranging from 0 to 14 that measures the acidity or alkalinity of a solution based on its hydrogen ion concentration.

Question 2: What pH value indicates a neutral solution? Name an example substance.

Answer: pH 7; pure water

Question 3: Which pH range corresponds to acids? Provide two examples of common acids.

Answer: pH less than 7; examples include lemon juice and vinegar.

Question 4: Describe how the pH scale is related to hydrogen ion concentration in a solution.

Answer: The pH scale is logarithmic; as pH decreases, hydrogen ion concentration increases exponentially, indicating higher acidity.

Question 5: Calculate the pH of a solution with a hydrogen ion concentration of 1 x 10^-4 mol/L.

Answer: pH = -log[H+]; pH = -log(1 x 10^-4) = 4

Question 6: Identify whether the following solutions are acidic, neutral, or alkaline: (a) Baking soda solution, (b) Hydrochloric acid, (c) Pure water.

Answer: a) Alkaline, b) Acidic, c) Neutral

Question 7: Fill in the blank: A solution with a pH of 3 is considered strongly __________.

Answer: acidic

Question 8: Explain why household vinegar is considered an acid based on its pH value.

Answer: Household vinegar has a pH less than 7, typically around 2-3, indicating it has a high concentration of hydrogen ions, making it acidic.

Question 9: Describe a simple experiment to test whether a liquid is an acid or a base, including safety precautions.

Answer: You can use pH indicator paper or a universal pH indicator solution. Dip the paper or add a few drops of the indicator to the liquid and observe the color change. Safety precautions include wearing gloves and eye protection to avoid contact with harmful substances and handling acids or bases carefully.

Question 10: In industrial applications, why is monitoring pH important in wastewater treatment?

Answer: Monitoring pH is important to ensure the wastewater is neutralized before discharge to prevent environmental damage and to optimize the efficiency of treatment processes.