Download App

Materials : Metals and Non-Metals — Science STD 8 — Question

Gujarat BoardEnglish MediumSTD 8ScienceMaterials : Metals and Non-Metals4 Marks
Question
Write the conditions under which rusting takes place.
✓

Answer

$i.$ When metals come in contact with air and water then rusting takes place. In iron, rusting is a process in which iron is oxidised into ferric oxide $(\ce{Fe_2O_3})$.
$ii.$ The presence of impurities in the iron like water vapours, acids, salts and carbon dioxide also responsible for rusting.
$iii.$ Iron does not rust in pure water which is free from dissolved salts.
$iv.$ Metals like chromium, zinc and magnesium prevent rusting. So zinc is used to galvanise the iron to prevent rusting of iron.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "questions in details [4 marks ]" from Materials : Metals and Non-Metals→Materials : Metals and Non-Metals — all question types→Science STD 8 question papers→Gujarat Board STD 8 question papers→Gujarat Board question paper generator→

Similar questions

Explain consequences of deforestation.
→
Describe an activity to show that a liquid exerts equal pressure in all the direction at a given depth.
→
What is night blindness? What causes night blindness?
→
Match the terms given in column I with their functions given in column II and fill the blanks given below the table:
S.No
Column I
S.No
Column II
$A$
Chloroplast
$i$
Carries hereditary characters
$B$
Cell membrane
$ii$
Controls the activities of cells
$C$
Nucleus
$iii$
Site of photosynthesis
$D$
Chromosome
$iv$
Controls the movement of materials into and out of cells.
→
Write short notes on the following. Nucleus of a cell.
→
Tabulate differences between plant and animal cell with diagram of onion peel cells and cheek cells.
→
The species $P$ and $Q$ of wild animals are found only in a ‘particular area’. The species $R$ of wild animals is listed in $R$ed data book of India whereas species $S$ of wild animals no longer exists anywhere on the earth.
$A.$ What name is given to species like $P$ and $Q$?
$B.$ What are the species like $R$ known as?
$C.$ Name one species like $R$?
$D.$ What is the special name of species like $S$?
$E.$ Name one species like $S$?
→
How does a Hydra reproduce? Explain with the help of labeled diagrams.
→
Write an activity to show that synthetic fibres are stronger than the cotton fibres.
→
Describe the various steps involved in the sexual reproduction in animals.
→