Download App

Chemistry [5 Mark Question Answer]

Analytical Chemistry · ICSE STD 10 (ICSE - English Medium). 2 questions.

Questions

[5 Mark Question Answer]

🎯

Test yourself on this topic

2 questions · timed · auto-graded

Question 15 Marks
A local water treatment plant is responsible for ensuring that the water supplied to the community is safe for consumption. Recently, there have been complaints about the taste and odor of the water. The plant decided to conduct a comprehensive water quality analysis to address these concerns. The analysis includes measuring pH, chlorine content, total dissolved solids (TDS), and detecting the presence of any heavy metals.
The results from the analysis are as follows: pH: 7.2
Chlorine Content: 0.8 ppm
TDS: 450 mg/L
Heavy Metals Detected: Trace amounts of lead (Pb) and arsenic (As)
(i) Evaluate the pH level of the water. Is it within the safe range for drinking water? Explain.
(ii) Discuss the significance of chlorine content in the water. Is the measured chlorine content within the acceptable limits?
(iii) Propose methods the water treatment plant could use to address the presence of heavy metals detected in the water.
(iv) What additional tests or analyses would you recommend to ensure comprehensive water quality assessment?
Answer
(i) The pH level of the water is 7.2. The safe range for drinking water is typically between 6.5 and 8.5. Since 7.2 falls within this range, the pH level of the water is considered safe for consumption. This indicates that the water is neither too acidic nor too alkaline, which is ideal for drinking purposes.
(ii) Chlorine is used in water treatment to kill bacteria and other pathogens. The acceptable limit for chlorine in drinking water.
(iii) Chromatography technique
(iv) Test for Hardness of water.
View full question & answer→
Question 25 Marks
You are provided with two separate colorless solutions. Solution A is suspected to contain either silver (Ag+) or copper(II) (Cu2+) ions, Solution B is suspected to contain either sulfate (SO42-) or carbonate (CO32-) ions.
Design a step-by-step procedure to identify the ions present in both solutions, detailing the reagents you would use, the observations you would expect, and the chemical equations for the reactions involved.
Answer
• Solution A: Test for Silver (Ag+) ions
Reagent: Add a few drops of dilute hydrochloric acid (HCl) to Solution A.Observation: Formation of a white precipitate indicates the presence of silver ions.
• Test for Copper(II) (Cu2+) ions
Reagent: If no precipitate forms with HCl2 add a few drops of sodium hydroxide (NaOH) to Solution A. Observation: Formation of a blue precipitate indicates the presence of copper(II) ions.
• Solution B: Test for Sulphate (SO42-) ions
Reagent: Add a few drops of barium chloride (BaCl2) to Solution B.Observation: Formation of a white precipitate indicates the presence of sulfate ions.
• Test for Carbonate (CO32-) ions:
Reagent: If no precipitate forms with BaCl2, add a few drops of dilute hydrochloric acid (HCl) to Solution B.Observation: Effervescence (bubbling) due to the release of carbon dioxide gas indicates the presence of carbonate ions. You can confirm by passing the gas through limewater, which will turn milky.
• Summary:
Solution A: Test with HCl and NaOH to identify Ag+ or Cu2+,
Solution B: Test with BaCl2 and HCl to identify SO42- or CO32-.
View full question & answer→
Generate Paper FreeAll Analytical Chemistry topics
[5 Mark Question Answer] - Chemistry STD 10 Questions - Vidyadip