List of top Chemistry Questions asked in NEET (UG)

The correct order of increasing thermal stability of $K_2CO_3, MgCO_3, CaCO_3 $ and $ BeCO_3$ is

The Langmuir adsorption isotherm is deduced by using the assumption :

Sulphide ores of metals are usually concentrated by froth floatation process. Which one of the following sulphide ores offers an exception and is concentrated by chemical leaching?

$RNA$ and $DNA$ are chiral molecules, their chirality is due to

For the following: (a) $I^-$ (b) $Cl^-$ (c) $Br^-$ The increasing order of nucleophilicity would be:

Consider the following sets of quantum number:

	n	$\ell$	m	s
(a)	3	0	0	$+1 / 2$
(b)	2	2	1	$+1 / 2$
(c)	4	3	-2	$-1 / 2$
(d)	1	0	-1	$-1 / 2$
(e)	3	2	3	$+1 / 2$

Which of the following sets of quantum number is not possible:

The number of moles of $KMnO_4$ that will be needed to react with one mole of sulphite ion in acidic solution is

The two polynucleotide chain in $DNA$ are :

Consider the following compounds: (i) $C_6H_5COCl$ The correct decreasing order of their reactivity towards hydrolysis is:

Which of the following will give a pair of enantiomers? (en $= NH_2CH_2CH_2NH_2$)

If $60\%$ of a first order reaction was completed in $60\, min$, $50\%$ of the same reaction would be completed in approximately ($log\, 4 = 0.60 \,log\, 5 = 0.69$)

The reaction of hydrogen an iodine monochloride is given as $H _{2( g )}+2 ICl _{( g )} \rightarrow 2 HCl _{( g )}+ I _{2( g )}$ This reaction is of first order with respect to $H _{2( g )}$ and $ICl _{( g )}$, following mechanisms were proposed Mechanism $A$: $H _{2( g )}+2 ICl _{( g )} \rightarrow 2 HCl _{( g )}+ I _{2( g )}$ Mechanism $B$ : $H _{2( g )}+ ICl _{( g )} \rightarrow HCl _{( g )}+ HI _{( g )} ;$ Slow $HI _{( g )}+ ICl _{( g )} \rightarrow HCl _{( g )}+ I _{2( g )} ;$ Fast Which of the above mechanism $(s)$ can be consistent with the given information about the reaction:

If there is no rotation of plane polarised light by a compound in a specific solvent, though to be chiral, it may mean that

An element, $X$ has the following isotopic composition; ${ }^{200} X : 90 \%$ ${ }^{199} X : 8.0 \%$ ${ }^{202} X : 2.0 \%$ The weighted average atomic mass of the naturally-occurring element $X$ is closest to:

With which of the following electronic configuration of an atom has the lowest ionisation enthalpy?

Identify the correct order of the size of the following.

Which of the following oxidation states are the most characteristics for lead and tin respectively?

Photochemical smog pollution does not contain:

Self condensation of two moles of ethyl acetate in presence of sodium ethoxide yields:

During osmosis, flow of water through a semi-permeable membrane is :

1.00 g of a non-electrolyte solute (molar mass 250 g mol^-1) was dissolved in 51.2 g of benzene. If the freezing point depression constant, K_f of benzene is 5.12 K kg mol^-1, the freezing point of benzene will be lowered by:

The general molecular formula, which represents the homologous series of alkanols is :

A carbonyl compound reacts with hydrogen cyanide to form cyanohydrin which on hydrolysis forms a racemic mixture of α-hydroxy acid. The carbonyl compound is:

In which of the following molecules are all the bonds not equal?

The electronegativity difference between N and F is greater than that between N and H yet the dipole moment of NH₃ (1.5 D) is larger than that of NF₃ (0.2 D). This is because: