NEET doubts
700 doubts found
Why are aldehydes generally more reactive than ketones towards nucleophiles?
The carbonyl carbon is the reactive spot, and two effects make aldehydes more open to attack.
Why is aniline a much weaker base than methylamine?
Basicity depends on how available the nitrogen's lone pair is to grab a proton.
What does “Molar mass” actually mean in Some Basic Concepts (Mole Concept), and why does it matter for NEET?
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 NEET?
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 NEET?
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 NEET?
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 NEET?
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 NEET?
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 NEET?
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 NEET?
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 NEET?
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 NEET?
delocalisation of electrons over several atoms, giving extra stability.
What does “Markovnikov's rule” actually mean in Hydrocarbons, and why does it matter for NEET?
when HX adds to an alkene, H attaches to the carbon that already has more hydrogens.
Why do raisins swell up in water but a cucumber shrivels into a pickle in brine?
It's osmosis, driven by the concentration difference across the cell membranes.
Why does window glass have no fixed melting point and can even slowly 'flow' over centuries?
Glass is amorphous — its particles are frozen in a disordered, liquid-like arrangement rather than a neat crystal lattice.
Why do scuba divers get 'the bends' if they surface too quickly?
Gas solubility rises with pressure (Henry's law).
Why is haemoglobin so good at carrying oxygen, and why is carbon monoxide so deadly?
Haemoglobin holds an Fe²⁺ ion in a porphyrin ring; oxygen binds reversibly to this iron centre as a ligand, so blood can pick up O₂ in the lungs and release it in the tissues.
Why must a Grignard reagent be made and used in perfectly dry conditions?
A Grignard reagent (R–MgX) has a strongly nucleophilic, basic carbon.
How does the Lucas test tell primary, secondary and tertiary alcohols apart?
The Lucas reagent (conc.
Why is acetic acid (vinegar) a stronger acid than phenol or ethanol?
When a carboxylic acid loses its O–H proton, the negative charge on the carboxylate is shared equally over two oxygen atoms by resonance, giving a very stable ion — so the acid readily gives up its proton.
How are diazonium salts used to make the bright dyes in clothes?
A primary aromatic amine treated with nitrous acid at low temperature (0–5°C) forms a diazonium salt.
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.