---
title: "Requisites of good paints; varnish"
subject: "Engineering Chemistry"
chapter: 8
key: "semester_2/engineering_chemistry:paint-requisites-varnish"
source: https://www.bctengineer.com/q/semester_2/engineering_chemistry/paint-requisites-varnish
site: BCT Engineering
---

# Requisites of good paints; varnish

Engineering Chemistry · Chapter 8: Lubricants and Paints

- Asked in: 2070 Bhadra, 2.5 marks
- Video: [AdsulPolytechnic_Basicscience_Chemistry_Lec_32_Paints -characteristics of good paint](https://www.youtube.com/watch?v=VEjglfPvafk) — Adsul Polytechnic
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_2/engineering_chemistry/paint-requisites-varnish
- Whole chapter: https://www.bctengineer.com/md/semester_2/engineering_chemistry/chapter-8

## Question

Mention the requisites of good paints and write about varnish.

## Short answer

Good paint spreads easily, dries to a hard tough elastic film that adheres well, resists weather and chemicals, and is cheap and non‑toxic. Varnish is a transparent solution of resin in drying oil or solvent, containing no pigment, used to give a glossy protective film on wood and over painted surfaces.

## Answer

#### Requisites of good paints
1. Easy to apply, with good covering power.
2. Dries quickly to a hard, tough and elastic film.
3. The film adheres well and does not crack or peel.
4. Resists weather, water and chemicals, and has a lasting colour.
5. Cheap and non-toxic.

#### Varnish
Varnish is a homogeneous solution of a resin (natural: shellac, copal, amber; or synthetic) in a drying oil or a volatile solvent such as turpentine or alcohol. It contains no pigment. On application the solvent evaporates and the oil dries to leave a transparent, glossy, hard protective film.
- **Types:** oil varnish (resin in drying oil + turpentine), spirit varnish (shellac in alcohol), water varnish.
- **Uses:** wooden furniture, doors and floors, and over painted surfaces to protect and brighten them.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is varnish?
   A. A dispersion of pigment in water
   B. A solution of resin in drying oil or volatile solvent, with no pigment
   C. A mixture of cement and pigment
   D. A solution of bitumen
   Answer: B. Varnish is a homogeneous resin solution with no pigment. (Key point: Varnish definition)

2. Why is the varnish film transparent?
   A. It has too much pigment
   B. It contains cement
   C. It is based on bitumen
   D. It contains no pigment
   Answer: D. No pigment, so the hard glossy film is transparent. (Key point: Appearance)

3. What is spirit varnish?
   A. Resin in linseed oil
   B. Shellac dissolved in alcohol
   C. Pigment in turpentine
   D. Cement in water
   Answer: B. Spirit varnish is shellac in alcohol; oil varnish is resin in drying oil + turpentine. (Key point: Spirit varnish)

4. Where is varnish used?
   A. Underground pipes
   B. Steel bridges as anticorrosive
   C. Inside engines
   D. On wooden furniture, doors and floors, and over paint
   Answer: D. Varnish protects and brightens wood and painted surfaces. (Key point: Uses)

## Related in Engineering Chemistry

- [Paint requisites and types of paints](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Apaint-requisites) — Engineering Chemistry, chapter 8
- [Enamel; requisites of paints](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Aenamel-paint-requisites) — Engineering Chemistry, chapter 8
- [Paint and requisites of a good paint](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Apaint-requisites-short) — Engineering Chemistry, chapter 8, asked 2×
- [Characteristics of good paints](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Apaint-characteristics) — Engineering Chemistry, chapter 8, asked 2×

## Related in other subjects

- [Paints, oil paint ingredients, painting woodwork](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Apaints-characteristics-066bh) — Building Technology, chapter 9
- [Requirements of good roof; pitched roof types](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aroof-requirements-pitch-066j) — Building Technology, chapter 4