Corrosion of metals and their protection

What is the chemical nature of rust?

• iron (II) oxide

• hydrated iron (II) oxide

• iron (III) oxide

• hydrated iron(III) oxide

What conditions are required for rusting?

• water only

• oxygen only

• water and oxygen

Tags

NGSS.MS-ESS2-4

Which diagram shows the most favourable conditions for rust to appear on the nail?

• A

• B

• C

• D

Tags

NGSS.MS-ESS2-4

NGSS.MS-PS1-2

The chemical formula of rust is

• Fe₂O₃

• Fe₂O₃.H₂O

• Fe₂O₃.xH₂0

Which of the following factors can speed up the rusting process?

I) ionic substances

II) acidic pollutants

III) high temperature

• I and II only

• I and III only

• II and III only

• I, II and III

Rust indicator is a mixture of potassium hexacyanoferrate(III) and phenolphthalein

• True

• False

Rust indicator will show a blue colour in the resence of

• Fe²⁺ ions

• Fe³⁺ ions

• Fe metal

Rust indicator will show a pink colour in the presence of

• H⁺ ions

• OH^- ions

Which of the following reaction will occur during rusting?

I) Fe --> Fe²⁺ + 2e^-

II) 2H₂O + O₂ + 4e^- ---> 4OH^-

III) Fe --> Fe³⁺ + 3e^-

• I and II only

• II and III only

• I , II and III

Which of the following is / are examples of sacrificial protection against rusting?

(1) Iron object coated with tin

(2) Underground iron pipes connected to magnesium bars

(3) Iron railings coated with paint

• (1) only

• (2) only

• (1) and (3) only

• (2) and (3) only