PLS FOUNDATION
Understand particles, reactions and the materials around you.
8 GUIDES · ENGLISH & HINDI
Start with a level that fits what you already know. Each guide includes explanations, practice and answers. About learning levels →
Chemistry
BeginnerA colour change can answer a chemical question, but only if we know what the indicator measures.
Learning outcome: Interpret litmus and pH records, distinguish strength from concentration, and explain the limits of a neutralisation claim.
Read the guide →Chemistry
BeginnerA cooking vessel, its handle and an electrical cable need different properties.
Learning outcome: Compare material properties, calculate an illustrative alloy composition, and explain how corrosion prevention must match the exposure.
Read the guide →Chemistry
BeginnerA puddle shrinks, a cold bottle becomes wet, and a balloon keeps its shape.
Learning outcome: Explain solids, liquids, gases, diffusion and changes of state, then use a mass balance and a temperature record to test a particle explanation.
Read the guide →Chemistry
BeginnerA formula is a compact statement about composition.
Learning outcome: Classify particle models, interpret subscripts and coefficients, and calculate atom counts and approximate molecular masses with meaningful units.
Read the guide →Chemistry
BeginnerClear water can still contain dissolved substances.
Learning outcome: Distinguish solutions, suspensions and colloids, calculate mass percentage, and justify a sequence of separation steps without confusing clarity with purity.
Read the guide →Chemistry
IntermediateThe periodic table is a map of relationships.
Learning outcome: Read a periodic-table entry, compare selected main-group elements, and justify a prediction while stating the limits of the pattern.
Read the guide →Chemistry
IntermediateA fuel, a food ingredient and a soap can all contain carbon while behaving very differently.
Learning outcome: Check simple carbon structures, distinguish a formula from connectivity, recognise two functional groups, and explain the two-part structure of soap.
Read the guide →Chemistry
IntermediateRusting and melting both change what we see, but only one forms new substances.
Learning outcome: Interpret reaction evidence, balance simple equations without changing formulas, and explain apparent mass gains or losses by tracing matter across a boundary.
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