NTA JEE Mains 28th Jan 2026 Shift 1 - Chemistry

In the given pentapeptide, find out an essential amino acid (Y) and the sequence present in the pentapeptide:

Choose the correct answer from the options given below:

Consider a weak base 'B' of $$pK_{b}=5.699 $$. 'x' mL of 0.02 M HCI and 'y' mL of 0.02 M weak base 'B' are mixed to make 100 mL of a buffer of pH 9 at 25 °C. The values of 'x' and 'y' respectively are:
[Given: log 2 = 0.3010, log 3 = 0.4771, log 5 = 0.699]

The correct statement among the followring is:

Given below are two statements:
Statement I: Griss-Ilosvay test is used for the detection of nitrite ion, which involves the use of sulphanilic acid and $$\alpha-naphthylamine$$ reagent.
Statement II: In the above test, sulphanilic acid is diazotized by the acidified nitrite ion, which on further coupling with $$\alpha-naphthylamine$$ forms an azo-dye.
In the light of the above statements, choose the correct answer from the options given below

In period 4 of the periodic table, the elements with highest and lowest atomic radii are respectively.

Consider the following reactions giving major product. Identify the correct reaction.

Given below are two statements:
Statement I: The number of pairs, from the following, in which both the ions are coloured in aqueous solution is 3.
$$[Sc^{3+},Ti^{3+}],[Mn^{2+},Cr^{2+}],[Cu^{2+},Zn^{2+}]$$ and $$[Ni^{2+},Ti^{4+}]$$
Statement II: $$Th^{4+}$$ is the strongest reducing agent among $$Th^{4+},Ce^{4+},Gd^{3+}\text{ and }Eu^{2+}$$.
In the light of the above statements, choose the correct answer from the options given below

Consider the following reaction sequence

Compound (y) develops characte1~stic colour with neutral $$FeCl_{3}$$ solution.
Identify the INCORRECT statement from the following for the above sequence.

An organic compound undergoes first order decomposition. The time taken for decomposition to $$\left(\frac{1}{8}\right)^{th}$$ and $$\left(\frac{1}{10}\right)^{th}$$ of its initial concentration are $$t_{1/8}$$ and $$t_{1/10}$$ respectively. What is the value of $$\frac{t_{1/8}}{t_{1/10}}\times 10$$ ?
$$(\log{2}=0.3)$$

$$20.0 dm^{3}$$ of an ideal gas 'X' at 600 K and 0.5 MPa undergoes isothermal reversible expansion until pressme of the gas is 0.2 MPa. Which of the following option is correct?
(Given: $$\log 2 = 0.30 10 and \log 5 = 0.6989$$)

Method used for separation of mixture of products (B and C) obtained in the following reaction is

Given below are two statements for the following reaction sequence.

Statement I: Compound 'Z' will give yellow precipitate with NaOI.
Statement II: Compound 'Q' has two different types of'H' atoms (aromatic:aliphatic) in the ratio 1 :3.
In the light of the above statements, choose the correct answer from the options given below:

At T(K), 2 moles of liquid A and 3 moles of liquid B are mixed. The vapour pressure of ideal solution fonned is 320 mm Hg. At this stage, one mole of A and one mole of B are added to the solution. The vapour pressure is now measmed as 328.6 mm Hg. The vapom pressure (in mm Hg) of A and B are respectively:

Given below are the four isomeric compounds (P, Q, R, S)

Identify correct statements from below
A. Q, R and S will give precipitate with 2, 4 - DNP.
B. P and Q will give positive Bayer's test.
C. Q and R will give sooty flame.
D. Rand S will give yellow precipitate with $$I_{2}/NaOH$$.
E. Q alone will deposit silver with Tollen's reagent.
Choose the correct option.

The wave numbers of three spectral lines of H atom are considered. Identify the set of spectral lines belonging to Balmer series.
(R = Rydberg constant)

Given below are two statements:
Statement I: The number of species among $$BF_{4}^{-},SiF_{4},XeF_{4}\text{ and }SF_{4}$$,that have unequal E-F bond lengths is two. Here, E is the central atom.
Satement II: Among $$O_{2}^{-},O_{2}^{2-},F_{2}\text{ and }O_{2}^{+},O_{2}^{-}$$ has the highest bond order.
In the light of the above statements, choose the correct answer from the options given below

CORRECT order of stability for the following is
$$CH_{2}=CH^{-},CH_{3}-CH_{2}^{-},CH\equiv C^{-}$$

Consider the above reaction
A. The reaction proceeds through a more stable radical intermediate.
B. The role of peroxide is to generate H^{.} (Hydrogen radical).
C. During this reaction, benzene is formed as a byproduct.
D. 1-Bromo-2- phenylethane is formed as the minor product.
E. The same reaction in absence of peroxide proceeds via carbocation intermediate.
Identify the correct statements. Choose the correct answer from the options given below:

Figure 1. electron probability density for 2s orbital

Figure 2. wave function for 2s orbital

 Which of the following point in Figure 2 most accurately represents the nodal surface as shown in Figure 1?

Regarding the hydrides of group 15 elements $$EH_{3}$$(E = N, P, As, Sb), select the correct statement from the following:
A. The stability of hydrides decreases down the group.
B. The basicity of hydrides decreases down the group.
C. The reducing character increases down the group.
D. The boiling point increases down the group.
Choose the correct answer from the options given below:

500 mL of 1.2 M KI solution is ,nixed with 500 mL of 0.2 M $$KMnO_{4}$$ solution in basic medium. The liberated iodine was titrated with standard 0.1 M $$Na_{2}S_{2}O_{3}$$ solution in the presence of starch indicator till the blue color disappeared. The volume (in L) of $$Na_{2}S_{2}O_{3}$$ consumed is_________.(Nearest integer)

X is the number of geometrical isomers exhibited by $$[Pt(NH_{3})(H_{2}O)BrCl]$$.
Y is the number of optically inactive isomer(s) exhibited by $$[CrCl_{2}(ox)_{2}]^{3-}$$
z is the number of geometrical isomers exhibited by $$[Co(NH_{3})_{3}(NO_{2})_{3}]$$.
The value of X + Y + Z is________.

0.53 g of an organic compound (x) when heated with excess of nitric acid ( concentrated) and then with silver nitrate gave 0. 75 g of silver bromide precipitate. 1.0 g of (x) gave 1.32 g of $$CO_{2}$$ gas on combustion. The percentage of hydrogen in the compound (x) is __ %. [Nearest Integer]
[Given: Molar mass in g $$mol^{-1}$$ H : 1, C : 12, Br: 80, Ag: 108, O : 16 ; Compound (x) :$$C_{x}H_{y}Br_{z}$$]

Consider the dissociation equilibrium of the following weak acid $$HA\rightleftharpoons H^{+}(aq)+A^{-}(aq)$$If the pKa of the acid is 4, then the pH of 10 mM HA solution is __ .(Nearest integer)
[Given: The degree of dissociation can be neglected with respect to unity]

Consider the following redox reaction taking place in acidic medium
$$BH_{4}^{-}(aq)+ClO_{3}^{-}(aq)\rightarrow H_{2}BO_{3}^{-}(aq)+Cl^{-}(aq)$$
If the Nerst equation for the above balanced reaction is $$E_{cell}=E_{cell}^{\circ}-\frac{RT}{nF}ln Q$$, then the value of n is______.(Nearest integer)