JEE · Chemistry doubts
161 doubts found
What is the difference between galvanic cell and electrolytic cell?
A galvanic cell produces electricity from a spontaneous reaction; an electrolytic cell consumes electricity to force a non-spontaneous one.
What is the difference between electrophile and nucleophile?
An electrophile accepts an electron pair (e.g. H⁺, NO₂⁺); a nucleophile donates one (e.g. OH⁻, NH₃).
What is the difference between saturated hydrocarbon and unsaturated hydrocarbon?
Saturated means maximum hydrogens and only single bonds; unsaturated has double/triple bonds and fewer hydrogens.
What is the difference between molarity and molality?
Molarity is per litre of solution (temperature-dependent); molality is per kg of solvent (temperature-independent).
What is the difference between shell and subshell?
A shell is a principal energy level (n); a subshell (s, p, d, f) is a division within a shell.
I keep getting “Hydrogen bonding” questions wrong in Chemical Bonding & Molecular Structure. What's the trap?
treating hydrogen bonds as ordinary covalent bonds.
What is the difference between exothermic reaction and endothermic reaction?
Exothermic releases heat (ΔH<0, surroundings warm); endothermic absorbs heat (ΔH>0, surroundings cool).
What is the difference between strong acid and weak acid?
A strong acid ionises completely (HCl); a weak acid ionises only partly (CH₃COOH) and has an equilibrium.
What are the most common mistakes students make in Redox Reactions?
the oxidising agent is itself reduced and the reducing agent is itself oxidised — name by what they DO to the other species.
What is the difference between metals and non-metals?
Metals lose electrons easily (low ionization energy, form cations); non-metals gain electrons (high electronegativity, form anions).
What is the difference between rate and rate constant?
Rate depends on concentration and changes as the reaction proceeds; the rate constant k is fixed at a given temperature.
What is the difference between anode and cathode?
Oxidation occurs at the anode and reduction at the cathode — in every cell, regardless of the terminal signs.
What is the difference between inductive effect and resonance effect?
The inductive effect works through sigma bonds and fades with distance; resonance works through pi systems and can act over long conjugation.
How is Hydrocarbons tested in JEE, and what should I focus on?
Prioritise the core ideas: Saturation, Markovnikov's rule, Aromaticity.
What is the difference between atomic mass and molar mass?
Atomic mass is for one atom (in u); molar mass is for one mole of them (in g/mol) — same number, different units.
What is the difference between Aufbau principle and Hund's rule?
Aufbau decides the ORDER subshells fill (low to high energy); Hund decides HOW electrons spread within a subshell (singly, same spin).
What is the difference between ionic bond and covalent bond?
An ionic bond transfers electrons (metal + non-metal, forms ions); a covalent bond shares electrons (between non-metals).
What is the difference between system and surroundings?
The system is the reaction you study; the surroundings are everything else that can exchange heat/work with it.
What is the difference between adding heat to exothermic and adding heat to endothermic?
Heating an exothermic reaction shifts it backward (toward reactants); heating an endothermic one shifts it forward (toward products).
How do I revise Redox Reactions quickly before the exam?
One-page summary of Oxidation and reduction, Oxidation number, Oxidising and reducing agents, then timed previous-year questions.
What is the difference between group and period?
A group is a vertical column (same valence electrons, similar properties); a period is a horizontal row (same number of shells).
What is the difference between catalyst on rate and catalyst on equilibrium?
A catalyst speeds a reaction by lowering activation energy but does NOT shift the equilibrium position.
When do I use E_cell = E_cathode − E_anode in Electrochemistry, and what does it mean?
standard cell EMF from electrode potentials.
What is the difference between SN1 reaction and SN2 reaction?
SN1 goes through a carbocation in two steps (favoured by 3° substrates); SN2 is a one-step backside attack (favoured by 1° substrates).