Who proposed the law of constant composition? MCQ with Answer and Explanation

Practice More chemistry Questions

Question #1

Share Report

Consider the following statements: 1. NPK fertilizers contain only macronutrients. 2. Zinc and Boron are micronutrients for plants. Which is/are correct?

A. Both 1 and 2

B. 2 only

C. Neither 1 nor 2

D. 1 only

View Answer & Solution Discuss

Correct Answer: Option A

---

Explanation:
NPK fertilizers supply the three primary macronutrients: Nitrogen (N), Phosphorus (P), and Potassium (K). Plants also require trace elements (micronutrients) in very small amounts for proper growth, such as Iron, Manganese, Zinc, Copper, Boron, and Molybdenum. Both statements are factually correct.

---

This question belongs to: Science chemistry

Report Question Issue

Help us improve! Please select the issue with this question:

-- Select an Issue -- Incorrect Answer Provided Formatting / Spelling Mistakes Incomplete Question or Options Question is in the Wrong Topic Explanation is incorrect/unclear Other Issue

Additional Details (Optional)

Cancel Submit Report

Question #2

Share Report

The process of separating petroleum into petrol, kerosene, diesel etc. is:

A. Fractional distillation

B. Reforming

C. Cracking

D. Polymerisation

View Answer & Solution Discuss

Correct Answer: Option A

---

Explanation:
Fractional distillation is the primary separation method in refining. Cracking breaks larger hydrocarbons into smaller ones (gasoline). Reforming alters structure to improve octane rating. Polymerisation combines small molecules. Fractional distillation separates based on boiling points in a fractionating column.

---

This question belongs to: Science chemistry

Report Question Issue

Help us improve! Please select the issue with this question:

-- Select an Issue -- Incorrect Answer Provided Formatting / Spelling Mistakes Incomplete Question or Options Question is in the Wrong Topic Explanation is incorrect/unclear Other Issue

Additional Details (Optional)

Cancel Submit Report

Question #3

Share Report

Which of the following metals is extracted by electrolytic reduction?

A. Zinc

B. Iron

C. Copper

D. Sodium

View Answer & Solution Discuss

Correct Answer: Option D

---

Explanation:
Highly reactive metals like sodium, potassium, calcium, and aluminum cannot be reduced by chemical reducing agents like carbon. They are extracted by the electrolysis of their molten chlorides or oxides. For example, sodium is extracted by the electrolysis of molten NaCl in the Down's cell.

---

This question belongs to: Science chemistry

Report Question Issue

Help us improve! Please select the issue with this question:

-- Select an Issue -- Incorrect Answer Provided Formatting / Spelling Mistakes Incomplete Question or Options Question is in the Wrong Topic Explanation is incorrect/unclear Other Issue

Additional Details (Optional)

Cancel Submit Report

Explore All chemistry MCQs

Fatal error: Uncaught PDOException: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'u220813639_questions.youtube_shorts' doesn't exist in /home/u220813639/domains/ask.jkexamlibrary.in/public_html/templates/partials/sidebar.php:55 Stack trace: #0 /home/u220813639/domains/ask.jkexamlibrary.in/public_html/templates/partials/sidebar.php(55): PDO->query() #1 /home/u220813639/domains/ask.jkexamlibrary.in/public_html/templates/question.php(278): require('/home/u22081363...') #2 /home/u220813639/domains/ask.jkexamlibrary.in/public_html/index.php(53): require_once('/home/u22081363...') #3 {main} thrown in /home/u220813639/domains/ask.jkexamlibrary.in/public_html/templates/partials/sidebar.php on line 55