Samacheer Kalvi 12th Chemistry Book Back Answers: All 15 Units

Class 12 Chemistry is the subject where the book back questions matter most, because the syllabus is broad and the exam is drawn very closely from the textbook evaluation sections. A student who has genuinely worked through all fifteen units of book back questions is in a strong position regardless of which guide they use.

The 15 units of 12th Chemistry

Unit	Title	Volume
1	Metallurgy	1
2	p-Block Elements I	1
3	p-Block Elements II	1
4	Transition and Inner Transition Elements	1
5	Coordination Chemistry	1
6	Solid State	1
7	Chemical Kinetics	1
8	Ionic Equilibrium	1
9	Electrochemistry	2
10	Surface Chemistry	2
11	Hydroxy Compounds and Ethers	2
12	Carbonyl Compounds and Carboxylic Acids	2
13	Organic Nitrogen Compounds	2
14	Biomolecules	2
15	Chemistry in Everyday Life	2

The three kinds of unit, and how to study each

Inorganic: units 1 to 5

Metallurgy, both p-block units, transition and inner transition elements, and coordination chemistry. These are memory-heavy, but the memory is structured rather than arbitrary. Group trends explain most of the individual facts, so learning the trend first makes the facts stick.

Coordination chemistry is the highest-return unit in this block. Nomenclature, isomerism, and crystal field theory colour and magnetic behaviour predictions appear reliably every year and are almost mechanical once learned.

Physical: units 6 to 10

Solid state, chemical kinetics, ionic equilibrium, electrochemistry and surface chemistry. This is where the numericals live, and where a well-prepared student picks up marks that memorisers cannot.

Priorities: packing efficiency and density of a unit cell, order of reaction and half life expressions, pH and buffer calculations using the Henderson equation, Nernst equation and cell emf, and the distinction between physisorption and chemisorption.

Organic: units 11 to 15

Hydroxy compounds and ethers, carbonyl compounds and carboxylic acids, organic nitrogen compounds, biomolecules and chemistry in everyday life.

Organic is where students most often try to memorise individual reactions and drown. The better approach is to learn the reagents. Once you know what LiAlH4, PCC, Tollens reagent, Fehling solution and hot alkaline KMnO4 each do, most conversion questions solve themselves without separate memorisation.

Question types you will meet in the evaluation sections

• Direct recall. Which ore, which catalyst, which reagent. Fast marks if revised, zero if not.
• Trend comparison. Arrange in order of acidity, basicity, stability or ionisation energy. These need the reason, not just the order, because the ordering questions get reversed year to year.
• Numericals. Concentrated in the physical chemistry units. Always write the formula on its own line before substituting.
• Identify the product. Common in organic. Work backwards from the reagent rather than trying to recall the specific reaction.
• Assertion and reason. Read both statements separately, decide the truth of each, and only then decide whether the second explains the first.

How to revise fifteen units without running out of time

Do not revise in textbook order. Revise in order of return:

1. Coordination chemistry, chemical kinetics, ionic equilibrium and electrochemistry first. Heavy, testable, and full of repeatable question types.
2. Organic units next, working from a single reagent sheet rather than reaction lists.
3. p-block and transition elements, using group trends as the spine.
4. Surface chemistry, biomolecules and chemistry in everyday life last. Short, factual, quick to secure.

The last group is the one students most often skip, and it is the cheapest set of marks in the entire subject. A single evening covers all three.

Practise rather than re-read

Chemistry rewards retrieval practice more than most subjects, because so much of it is recall under time pressure. Convert the book back questions into timed sets rather than reading them, and keep a one-page list of the facts you keep forgetting. That page is your final week revision.

More Class 12 chapter-wise material is being added on the Class 12 section.