NEET doubts
700 doubts found
What does “Electrode potential” actually mean in Electrochemistry, and why does it matter for NEET?
the tendency of an electrode to gain electrons; cell EMF = E(cathode) − E(anode).
What does “Electrophiles and nucleophiles” actually mean in Organic Chemistry — Basic Concepts, and why does it matter for NEET?
electrophiles are electron-poor (seek electrons); nucleophiles are electron-rich (donate electrons).
What does “Aromaticity” actually mean in Hydrocarbons, and why does it matter for NEET?
extra stability of planar, cyclic, fully-conjugated rings with (4n+2) pi electrons (benzene).
How does a reverse-osmosis (RO) purifier turn salty water into drinking water?
Normally osmosis drives pure water toward the salty side.
What does “Crystalline vs amorphous” actually mean in The Solid State, and why does it matter for NEET?
crystalline solids have long-range ordered arrangement and sharp melting points; amorphous solids (glass) lack order and soften over a range.
Open a perfume bottle in one corner and the whole room smells it — why, and what's fastest?
Gas molecules are in constant rapid random motion, so they diffuse and spread until evenly mixed, even against still air.
What does “Ligands & coordination number” actually mean in Coordination Compounds, and why does it matter for NEET?
ligands are electron-pair donors bonded to a central metal ion; the coordination number is how many donor atoms attach to it.
What does “Nucleophilic substitution” actually mean in Haloalkanes & Haloarenes, and why does it matter for NEET?
a nucleophile replaces the halogen; it can go by SN1 (two steps, via a carbocation) or SN2 (one step, backside attack).
What does “Acidity of alcohols vs phenols” actually mean in Alcohols, Phenols & Ethers, and why does it matter for NEET?
phenols are far more acidic than alcohols because the phenoxide ion is stabilised by resonance into the ring.
What does “Nucleophilic addition to carbonyls” actually mean in Aldehydes, Ketones & Carboxylic Acids, and why does it matter for NEET?
the polar C=O group is attacked by nucleophiles at carbon; aldehydes react faster than ketones.
What does “Basicity of amines” actually mean in Amines & Biomolecules, and why does it matter for NEET?
amines are basic because the nitrogen lone pair can accept a proton; aliphatic amines are more basic than ammonia, aniline is less.
I keep getting “Limiting reagent” questions wrong in Some Basic Concepts (Mole Concept). What's the trap?
assuming the reactant with the smaller mass is limiting.
I keep getting “Filling rules” questions wrong in Structure of Atom. What's the trap?
pairing electrons in a subshell before every orbital has one.
I keep getting “Hybridization” questions wrong in Chemical Bonding & Molecular Structure. What's the trap?
predicting geometry without counting lone pairs in the hybridization.
I keep getting “Gibbs free energy” questions wrong in Chemical Thermodynamics. What's the trap?
judging spontaneity from ΔH alone.
I keep getting “Equilibrium constant” questions wrong in Equilibrium. What's the trap?
including pure solids/liquids in the K expression.
I keep getting “Oxidising and reducing agents” questions wrong in Redox Reactions. What's the trap?
calling the substance that is oxidised the 'oxidising agent'.
I keep getting “Electronegativity” questions wrong in Periodic Table & Periodicity. What's the trap?
assuming metals have high electronegativity.
I keep getting “Activation energy” questions wrong in Chemical Kinetics. What's the trap?
thinking a catalyst changes ΔH or the position of equilibrium.
I keep getting “Electrode potential” questions wrong in Electrochemistry. What's the trap?
forgetting to keep reduction potentials consistent when subtracting.
I keep getting “Electrophiles and nucleophiles” questions wrong in Organic Chemistry — Basic Concepts. What's the trap?
swapping the two definitions.
I keep getting “Aromaticity” questions wrong in Hydrocarbons. What's the trap?
expecting benzene to undergo addition like an alkene.
At the same concentration, why does calcium chloride melt ice better than glucose?
Colligative effects depend on the number of dissolved particles, captured by the van't Hoff factor i.
I keep getting “Crystalline vs amorphous” questions wrong in The Solid State. What's the trap?
calling glass a true crystalline solid.