Question 7
In certain reactions an insoluble solid called precipitate is formed. State the colour and name of the precipitate formed in each of the following reactions involving addition of:
(a) Dilute hydrochloric acid to silver nitrate
(b) Iron [II] sulphate to sodium hydroxide
(c) Iron [III] chloride to ammonium hydroxide
(d) Copper [II] sulphate to sodium hydroxide
(e) Lead nitrate to ammonium hydroxide
| S. No. | Name of precipitate | Colour of precipitate |
|---|---|---|
| (a) | Silver Chloride | Milky White |
| (b) | Iron [II] hydroxide | Dirty Green |
| (c) | Iron [III] hydroxide | Reddish Brown |
| (d) | Copper [II] hydroxide | Pale Blue |
| (e) | Lead hydroxide | Chalky White |
ICSE Class VII Chemistry Chapter 4 12 Marks
Language of Chemistry — Quick Study Guide
Chemical symbols, formulae, and equations are the language chemists use to describe substances and reactions.
Key Concepts
- Chemical symbol: Shorthand for an element (first letter capital, second lowercase)
- Chemical formula: Shows types and numbers of atoms in a molecule
- Cross-multiplication: Write symbols → valencies → cross → simplify
- Balanced equation: Same number of each atom on both sides
- Combination reaction: A + B → AB
- Decomposition reaction: AB → A + B
Latin-Origin Symbols to Memorise
Na (Sodium), Fe (Iron), Au (Gold), Ag (Silver), K (Potassium), Cu (Copper), Hg (Mercury), Pb (Lead), Sn (Tin)
Exam Tips
- Never change subscripts when balancing — only change coefficients
- Use brackets for polyatomic ions when subscript > 1
- Practice writing formulae using cross-multiplication daily
- CO ≠ Co (carbon monoxide vs cobalt)
Bright Tutorials | ICSE Class VII Chemistry | Chapter 4: Language of Chemistry | Contact: 9403781999