alleryWhy can a layer of paint not protect an iron article from rusting permanently?
AA scratch lets air reach the bare metal
BPaint chemically reacts with the iron
CPaint dissolves the protective oxide layer
DPaint attracts more moisture to the iron
Answer & Solution
Correct answer: A. A scratch lets air reach the bare metal
1. Painting isolates the metal from air and moisture for a while.
2. If the paint gets scratched, a small bare surface of iron is exposed.
3. Air and moisture then reach this exposed metal and rusting starts beneath the paint.
4. The paint does not react with or dissolve into the iron, so those options are wrong.
_Source: Balbharati (Maharashtra Board) Class 10 Science & Technology, Ch 8 "Metallurgy", p.116_
Keep practising Unit 4B1: Properties of Metals and Non-Metals
Browse all Unit 4B1: Properties of Metals and Non-Metals questions for Maharashtra SSC (Class 10), or explore more Chemistry topics.
Related questions
Bronze, an alloy resistant to sun and rain, is made from which composition?An alloy in which one of the constituent metals is mercury is given which special name?In electroplating, what is coated onto a more reactive metal by electrolysis?In anodization of aluminium, the article is made the anode so that a protective layer of wDepositing a layer of molten tin on a metal surface, popularly called 'kalhaee', is known In galvanizing, why does the zinc layer corrode before the iron beneath it?In galvanizing, a thin layer of which metal is applied to protect iron or steel?The greenish layer that forms on a copper vessel kept in moist air is mainly which compoun