Question map
Not attempted Correct Incorrect ★ Bookmarked
Loading…
Q127 (IAS/1999) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Applied everyday chemistry Answer Verified

Consider the following statements : Glass can be etched or scratched by I. diamond. II. hydrofluoric acid. III. aquaregia. IV. cone, sulphuric acid. Which of these statements are correct ?

Result
Your answer: —  Â·  Correct: C
Explanation

Diamond, being the hardest natural material, will scratch typical glass surfaces (Mohs hardness: diamond 10 vs glass ≈6–7), so statement I is correct. Hydrofluoric acid chemically etches glass by reacting with silica (SiO2) to form volatile SiF4 and soluble hexafluorosilicic species, making statement II correct. Aqua regia is a powerful oxidizing mixture effective at dissolving noble metals but is not used to etch silica-based glass; concentrated sulfuric acid is a strong dehydrating acid but is far less effective for attacking glass than HF, so statements III and IV are not correct. Therefore, only I and II are correct.

How others answered
Each bar shows the % of students who chose that option. Green bar = correct answer, blue outline = your choice.
Community Performance
Out of everyone who attempted this question.
47%
got it right
✓ Thank you! We'll review this.

SIMILAR QUESTIONS

NDA-I · 2009 · Q97 Relevance score: 0.47

Consider the following statements regarding diamond : 1. It is an allotrope of silicon. 2. It is a bad conductor of heat and electricity. 3. Tt is the hardest substance. 4. It burns to produce carbon dioxide Which of the statements given above are correct?

CAPF · 2008 · Q113 Relevance score: -1.63

Consider the following statements : 1. Baking soda is used in fire extinguishers. 2. Quick lime is used in the manufacture of glass. Which of the statements given above is/are correct ?

IAS · 2004 · Q56 Relevance score: -1.64

Consider the following statements: 1. Baking soda is used in fire extinguishers. 2. Quicklime is used in the manufacture of glass. 3. Gypsum is used in the manufacture of Plaster of Paris. Which of the statements given above is/are correct ?

NDA-II · 2012 · Q76 Relevance score: -1.77

Consider the following statements: 1. Diamond is hard and graphite is soft. 2. Diamond is soft and graphite is hard. 3. Diamond is a bad conductor, but graphite is a good conductor. 4. Diamond is a good conductor, but graphite is a bad conductor. Which of the statement(s) given above is/are correct?

IAS · 1995 · Q108 Relevance score: -2.10

Assertion (A) : A diamond sparkles more than a glass imitation cut to the same shape. Reason (R) : The refractive index of diamond is less than that of glass. In the context of the above two statements, which one of the following is correct ?