Physical and Chemical Changes — Science STD 7 — Question
Gujarat BoardEnglish MediumSTD 7SciencePhysical and Chemical Changes1 Mark
MCQ
Which conditions are necessary for rusting?
A
Oxygen
B
Sunlight, water and metal
✓
Water, oxygen, a metal
D
Metal and oxygen
✓
Answer
Correct option: C.
Water, oxygen, a metal
Rusting takes place when there is contact between water, metal, and oxygen.
$\ce{4Fe + 3O_2 + 2nH_2O \longrightarrow 2Fe_2O_3. nH_2O}$
$($Iron$) ($oxygen$) ($water$) ($rust$)$
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