Graphite is used as a dry lubricant because: MCQ with Answer and Explanation

Graphite is used as a dry lubricant because:
A. It is soft like diamond
B. It reacts with the metal surface
C. It is a liquid
D. It has a layered structure that allows sheets to slide
Answer: Option D
Solution (By JKExamLibrary)
Graphite's carbon atoms are arranged in layers held together by weak van der Waals forces. Layers can slide over each other, reducing friction. It is stable at high temperatures, so used where oil would decompose.

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More chemistry Questions

Question #1
Glass is considered a:
A. Molecular solid
B. Amorphous solid
C. Ionic solid
D. Crystalline solid

Correct Answer: Option B


Explanation:
Glass is an amorphous (non-crystalline) solid, sometimes called a supercooled liquid. It lacks long-range periodic order; atoms are arranged in a disordered network. It softens over a temperature range rather than having a sharp melting point. Common glass is soda-lime-silicate glass. Crystalline solids have sharp melting points and regular lattice structures (e.g., NaCl, quartz).

This question belongs to: Science chemistry
Question #2
Faraday's first law: mass deposited ∝ quantity of electricity. The constant of proportionality (electrochemical equivalent) depends on:
A. Current
B. Temperature
C. Nature of the substance
D. Time

Correct Answer: Option C


Explanation:
Electrochemical equivalent (Z) is mass deposited per unit charge. It depends on molar mass and number of electrons transferred (valency). Z = M/(nF). It differs for different substances. Current and time affect total charge but not Z.

This question belongs to: Science chemistry
Question #3
Which of the following elements has the highest second ionization energy?
A. Silicon
B. Aluminum
C. Sodium
D. Magnesium

Correct Answer: Option C


Explanation:
Sodium has the electronic configuration [Ne]3s1. After losing one electron to form Na+, it achieves a highly stable noble gas configuration ([Ne]). Removing a second electron from this stable core requires an exceptionally large amount of energy. Thus, sodium has the highest second ionization energy among these elements.

This question belongs to: Science chemistry