NEET 2025

If the half-life ( $t_{1 / 2}$ ) for a first order reaction is 1 minute, then the time required for $99.9 \%$ completion of the reaction is closest to :

Out of the following complex compounds, which of the compound will be having the minimum conductance solution?

Which of the following are paramagnetic?
A. $\left[\mathrm{NiCl}_4\right]^{2-}$
B. $\mathrm{Ni}(\mathrm{CO})_4$
C. $\left[\mathrm{Ni}(\mathrm{CN})_4\right]^{2-}$
D. $\left[\mathrm{Ni}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$
E. $\...

The correct order of the wavelength of light absorbed by the following complexes is,
A. $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right]^{3+}$
B. $\left[\mathrm{Co}(\mathrm{CN})_6\right]^{3-}$
C. $\left[\mathrm{Cu}\left(\mathrm{H}_2 \m...

Match List - I with List - II.

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Given below are two statements :
Statement I: Ferromagnetism is considered as an extreme form of paramagnetism.
Statement II : The number of unpaired electrons in a $\mathrm{Cr}^{2+}$ ion $(\mathrm{Z}=24)$ is the same as that of a $\mathrm{...

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) :

undergoes $S_N 2$ reaction faster than

Reason (R) : lodine is a better leaving group because of its large size.
In ...

The major product of the following reaction is

Which one of the following reactions does NOT give benzene as the product?

Predict the major product ' $P$ ' in the following sequence of reactions-

Which one of the following compounds does not decolourize bromine water?

If the molar conductivity $\left(\Lambda_{\mathrm{m}}\right)$ of a $0.050 \mathrm{~mol} \mathrm{~L}^{-1}$ solution of a monobasic weak acid is $90 \mathrm{~S} \mathrm{~cm}^2 \mathrm{~mol}^{-1}$, its extent (degree) of dissociation will be
[...

Phosphoric acid ionizes in three steps with their ionization constant values $K_{a_1}, K_{a_2}$ and $K_{a_3}$, respectively, while $K$ is the overall ionization constant. Which of the following statements are true?
A. $\quad \log \mathrm{K}...

The correct order of decreasing basic strength of the given amines is:

Answer (1)
Sol. Lower is the value of $\mathrm{pK}_{\mathrm{b}}$, higher is the basicity
Also aliphatic amines are stronger bases than aromatic amines.
$\mathrm{pK}_{\m...

Given below are two statements :
Statement-I : Benzenediazonium salt is prepared by the reaction of aniline with nitrous acid at $273-278 \mathrm{~K}$. It decomposes easily in the dry state.
Statement-II : Insertion of iodine into the benze...

Given below are two statements :
Statement I: Like nitrogen that can form ammonia, arsenic can form arsine.
Statement II: Antimony cannot form antimony pentoxide.
In the light of the above statements, choose the most appropriate answer from...

Which of the following statements are true?
A. Unlike Ga that has a very high melting point, Cs has a very low melting point.
B. On Pauling scale, the electronegativity values of N and Cl are not the same.
C. $\mathrm{Ar}, \mathrm{K}^{+}, \...

Which among the following electronic configurations belong to main group elements?
A. $[\mathrm{Ne}] 3 \mathrm{~s}^1$
B. $[\operatorname{Ar}] 3 \mathrm{~d}^3 4 \mathrm{~s}^2$
C. $[K r] 4 d^{10} 5 s^2 5 p^5$
D. $[\operatorname{Ar}] 3 \mathrm...

Consider the following compounds :
${\mathrm{\underline{K}O}}_2, \mathrm{H}_2 \underline{\mathrm{O}}_2$ and $\mathrm{H}_2 \underline{S }O_4$
The oxidation state of the underlined elements in them are, respectively,

Which one of the following reactions does NOT belong to "Lassaigne's test"?

Which of the following aqueous solution will exhibit highest boiling point?

5 moles of liquid X and 10 moles of liquid Y make a solution having a vapour pressure of 70 torr. The vapour pressures of pure $X$ and $Y$ are 63 torr and 78 torr respectively. Which of the following is true regarding the described solution...

Match List-I with List-II

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Among the following, choose the ones with equal number of atoms.
A. 212 g of $\mathrm{Na}_2 \mathrm{CO}_3(\mathrm{~s})$ [molar mass $=106 \mathrm{~g}$ ]
B. 248 g of $\mathrm{Na}_2 \mathrm{O}(\mathrm{s})$ [molar mass $=62 \mathrm{~g}$ ]
C. 2...

Dalton's Atomic theory could not explain which of the following?

Match List-I with List-II

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...

Match List-I with List-II

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Which one of the following compounds can exist as cis-trans isomers?

How many products (including stereoisomers) are expected from monochlorination of the following compound?

Among the given compounds I-III, the correct order of bond dissociation energy of C-H bond marked with * is :

Total number of possible isomers (both structural as well as stereoisomers) of cyclic ethers of molecular formula $\mathrm{C}_4 \mathrm{H}_8 \mathrm{O}$ is :

The ratio of the wavelengths of the light absorbed by a Hydrogen atom when it undergoes $n=2 \rightarrow n=3$ and $n=4 \rightarrow$ $\mathrm{n}=6$ transitions, respectively, is

Energy and radius of first Bohr orbit of $\mathrm{He}^{+}$and $\mathrm{Li}^{2+}$ are [Given $\mathrm{R}_{\mathrm{H}}=2.18 \times 10^{-18} \mathrm{~J}, \mathrm{a}_0=52.9 \mathrm{pm}$ ]

The standard heat of formation, in $\mathrm{kcal} / \mathrm{mol}$ of $\mathrm{Ba}^{2+}$ is :
[Given : standard heat of formation of $\mathrm{SO}_4^{2-}$ ion $(\mathrm{aq})=-216 \mathrm{kcal} / \mathrm{mol}$, standard heat of crystallisation...

$\mathrm{C}(\mathrm{s})+2 \mathrm{H}_2(\mathrm{~g}) \rightarrow \mathrm{CH}_4(\mathrm{~g}) ; \Delta \mathrm{H}=-74.8 \mathrm{~kJ} \mathrm{~mol}^{-1}$. Which of the following diagrams gives an accurate representation of the above reaction? [...

To an ac power supply of 220 V at 50 Hz , a resistor of $20 \Omega$, a capacitor of reactance $25 \Omega$ and an inductor of reactance $45 \Omega$ are connected in series. The corresponding current in the circuit and the phase angle between...

A particle of mass $m$ is moving around the origin with a constant force $F$ pulling it towards the origin. If Bohr model is used to describe its motion, the radius of the $n^{\text {th }}$ orbit and the particle's speed $v$ in the orbit de...

The plates of a parallel plate capacitor are separated by $d$. Two slabs of different dielectric constant $K_1$ and $K_2$ with thickness $\frac{3}{8} d$ and $\frac{d}{2}$, respectively are inserted in the capacitor. Due to this, the capacit...

A ball of mass 0.5 kg is dropped from a height of 40 m . The ball hits the ground and rises to a height of 10 m . The impulse imparted to the ball during its collision with the ground is (Take $g=9.8 \mathrm{~m} / \mathrm{s}^2$ )

A wire of resistance $R$ is cut into 8 equal pieces. From these pieces two equivalent resistances are made by adding four of these together in parallel. Then these two sets are added in series. The net effective resistance of the combinatio...

The current passing through the battery in the given circuit, is:

A constant voltage of 50 V is maintained between the points $A$ and $B$ of the circuit shown in the figure. The current through the branch $C D$ of the circuit is:

A photon and an electron (mass $m$ ) have the same energy $E$. The ratio ( $\lambda_{\text {photon }} / \lambda_{\text {electron }}$ ) of their de Broglie wavelengths is: ( $c$ is the speed of light)

De-Broglie wavelength of an electron orbiting in the $n=2$ state of hydrogen atom is close to
(Given Bohr radius $=0.052 \mathrm{~nm}$ )

Which of the following options represent the variation of photoelectric current with property of light shown on the x-axis?

$A B$ is a part of an electrical circuit (see figure). The potential difference " $V_A-V_B$ ", at the instant when current $i=2 \mathrm{~A}$ and is increasing at a rate of $1 \mathrm{amp} /$ second is:

The electric field in a plane electromagnetic wave is given by \(E_z=60 \cos \left(5 x+1.5 \times 10^9 t\right) \mathrm{V} / \mathrm{m}\) Then expression for the corresponding magnetic field is (here subscripts denote the direction of the ...

An electric dipole with dipole moment $5 \times 10^{-6} \mathrm{Cm}$ is aligned with the direction of a uniform electric field of magnitude $4 \times 10^5 \mathrm{~N} / \mathrm{C}$. The dipole is then rotated through an angle of $60^{\circ}...

Two identical charged conducting spheres $A$ and $B$ have their centres separated by a certain distance. Charge on each sphere is $q$ and the force of repulsion between them is $F$. A third identical uncharged conducting sphere is brought i...

In a certain camera, a combination of four similar thin convex lenses are arranged axially in contact. Then the power of the combination and the total magnification in comparison to the power ( $p$ ) and magnification ( $m$ ) for each lens ...