JEE doubts
500 doubts found
I keep getting “Inductive effect” questions wrong in Organic Chemistry — Basic Concepts. What's the trap?
thinking the inductive effect travels undiminished along a chain.
I keep getting “Saturation” questions wrong in Hydrocarbons. What's the trap?
thinking unsaturated hydrocarbons are less reactive than alkanes.
What does “Molar mass” actually mean in Some Basic Concepts (Mole Concept), and why does it matter for JEE?
the mass of one mole of a substance in grams, numerically equal to its atomic/molecular mass.
What does “Orbitals” actually mean in Structure of Atom, and why does it matter for JEE?
regions around the nucleus where an electron is most likely to be found (s spherical, p dumbbell).
What does “VSEPR theory” actually mean in Chemical Bonding & Molecular Structure, and why does it matter for JEE?
electron pairs around a central atom arrange to be as far apart as possible, fixing the molecule's shape.
What does “Entropy (S)” actually mean in Chemical Thermodynamics, and why does it matter for JEE?
a measure of disorder or the number of ways energy can be arranged.
What does “Le Chatelier's principle” actually mean in Equilibrium, and why does it matter for JEE?
if you disturb a system at equilibrium, it shifts to oppose the change.
What does “Oxidation number” actually mean in Redox Reactions, and why does it matter for JEE?
a bookkeeping charge assigned by rules to track electron transfer.
What does “Ionization energy” actually mean in Periodic Table & Periodicity, and why does it matter for JEE?
the energy to remove the outermost electron; it rises across a period and falls down a group.
What does “Rate constant” actually mean in Chemical Kinetics, and why does it matter for JEE?
the proportionality constant k in the rate law; it rises sharply with temperature.
What does “Anode and cathode” actually mean in Electrochemistry, and why does it matter for JEE?
oxidation always happens at the anode and reduction always at the cathode.
What does “Resonance” actually mean in Organic Chemistry — Basic Concepts, and why does it matter for JEE?
delocalisation of electrons over several atoms, giving extra stability.
What does “Markovnikov's rule” actually mean in Hydrocarbons, and why does it matter for JEE?
when HX adds to an alkene, H attaches to the carbon that already has more hydrogens.
I keep getting “Molar mass” questions wrong in Some Basic Concepts (Mole Concept). What's the trap?
using atomic number instead of atomic mass to find molar mass.
I keep getting “Orbitals” questions wrong in Structure of Atom. What's the trap?
drawing fixed circular orbits (Bohr) instead of probability clouds.
I keep getting “VSEPR theory” questions wrong in Chemical Bonding & Molecular Structure. What's the trap?
counting only bonding pairs and ignoring lone pairs.
I keep getting “Entropy (S)” questions wrong in Chemical Thermodynamics. What's the trap?
thinking entropy always increases for the system alone.
I keep getting “Le Chatelier's principle” questions wrong in Equilibrium. What's the trap?
predicting the wrong direction of shift.
I keep getting “Oxidation number” questions wrong in Redox Reactions. What's the trap?
forgetting that oxidation number can be fractional or zero (e.g. in O₂, it's 0).
I keep getting “Ionization energy” questions wrong in Periodic Table & Periodicity. What's the trap?
ignoring small dips (e.g. B<Be, O<N) caused by sub-shell stability.
I keep getting “Rate constant” questions wrong in Chemical Kinetics. What's the trap?
thinking k depends on concentration.
I keep getting “Anode and cathode” questions wrong in Electrochemistry. What's the trap?
assuming the anode is always the positive terminal.
I keep getting “Resonance” questions wrong in Organic Chemistry — Basic Concepts. What's the trap?
believing the separate resonance structures actually exist and interconvert.
I keep getting “Markovnikov's rule” questions wrong in Hydrocarbons. What's the trap?
reversing it, except in the peroxide (anti-Markovnikov) effect.