Download JEE Advanced 2025 Chemistry Question Paper - 1

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SECTION 1 (Maximum Marks:12)

• This section contains FOUR (04) questions.
• Each question has FOUR options (A), (B), (C) and (D). ONLY ONE of these four options is the correct answer.
• For each question, choose the option corresponding to the correct answer.
• Answer to each question will be evaluated according to the following marking scheme:
  
  
  • Full Marks: +3 If ONLY the correct option is chosen;
  • Zero Marks: 0 If none of the options is chosen (i.e. the question is unanswered);
  • Negative Marks: -1 In all other cases.

1. The heating of $NH_4NO_2$ at $60−70 °C$ and $NH_4NO_3$ at $200−250 °C$ is associated with the formation of nitrogen containing compounds $X$ and $Y$, respectively. $X$ and $Y$, respectively, are
    
   1. $N_2$ and $N_2O$
   2. $NH_3$ and $NO_2$
   3. $NO$ and $N_2O$
   4. $N_2$ and $NH_3$
2. The correct order of the wavelength maxima of the absorption band in the ultraviolet-visible regionfor the given complexes is
    
   1. $[Co(CN)_6]^{3−}$ < $[Co(NH_3)_6]^{3+}$ < $[Co(NH_3)_5(H_2O)]^{3+}$ < $[Co(NH_3)_5(Cl)]^{2+}$
   2. $[Co(NH_3)_5(Cl)]^{2+}$ < $[Co(NH_3)_5(H_2O)]^{3+}$ < $[Co(NH_3)_6]^{3+}$ < $[Co(CN)_6]^{3−}$
   3. $[Co(CN)_6]^{3−}$ < $[Co(NH_3)_5(Cl)]^{2+}$ < $[Co(NH_3)_5(H_2O)]^{3+}$ < $[Co(NH_3)_6]^{3+}$
   4. $[Co(NH_3)_6]^{3+}$ < $[Co(CN)_6]^{3−}$ < $[Co(NH_3)_5(Cl)]^{2+}$ < $[Co(NH_3)_5(H_2O)]^{3+}$
3. One of the products formed from the reaction of permanganate ion with iodide ion in neutral aqueous medium is
    
   1. $I_2$
   2. $IO_3^{-}$
   3. $IO_4^{-}$
   4. $IO_2^{-}$
4. Consider the depicted hydrogen $(H)$ in the hydrocarbons given below. The most acidic hydrogen $(H)$ is
   1. 
      
   2. 
      
   3. 
      
   4. 
      

SECTION 2 (Maximum Marks:12)

• This section contains THREE (03) questions.
• Each question has FOUR options (A), (B), (C) and (D). ONE OR MORE THAN ONE of these four option(s) is(are) correct answer(s).
• For each question, choose the option(s) corresponding to (all) the correct answer(s).
• Answer to each question will be evaluated according to the following marking scheme:
  
  • Full Marks: +4 ONLY if (all) the correct option(s) is(are) chosen;
  • Partial Marks: +3 If all the four options are correct but ONLY three options are chosen;
  • Partial Marks: +2 If three or more options are correct but ONLY two options are chosen, both of which are correct;
  • Partial Marks: +1 If two or more options are correct but ONLY one option is chosen and it is a correct option;
  • Zero Marks: 0 If none of the options is chosen (i.e. the question is unanswered);
  • Negative Marks: -2 In all other cases.
• For example, in a question, if (A), (B) and (D) are the ONLY three options corresponding to correct answers, then
  choosing ONLY (A), (B) and (D) will get +4 marks;
  choosing ONLY (A) and (B) will get +2 marks;
  choosing ONLY (A) and (D) will get +2 marks;
  choosing ONLY (B) and (D) will get +2 marks;
  choosing ONLY (A) will get +1 mark;
  choosing ONLY (B) will get +1 mark;
  choosing ONLY (D) will get +1 mark;
  choosing no option (i.e. the question is unanswered) will get 0 marks; and choosing any other combination of options will get -2 marks.

5. Regarding the molecular orbital $(MO)$ energy levels for homonuclear diatomic molecules, the INCORRECT statement(s) is(are)
    
   1. Bond order of $Ne_2$ is zero.
   2. The highest occupied molecular orbital (HOMO) of $F_2$ is σ-type.
   3. Bond energy of $O_2^{+}$ is smaller than the bond energy of $O_2$.
   4. Bond length of $Li_2$ is larger than the bond length of $B_2$.
6. The pair(s) of diamagnetic ions is(are)
    
   1. $La^{3+}$, $Ce^{4+}$
   2. $Yb^{2+}$, $Lu^{3+}$
   3. $La^{2+}$, $Ce^{3+}$
   4. $Yb^{3+}$, $Lu^{2+}$
7. For the reaction sequence given below, the correct statement(s) is(are)
   
   
   
   
   (In the options, X is any atom other than carbon and hydrogen, and it is different in P, Q and R)
    
   1. C−X bond length in P, Q and R follows the order Q > R > P.
   2. C−X bond enthalpy in P, Q and R follows the order R > P > Q.
   3. Relative reactivity toward SN2 reaction in P, Q and R follows the order P > R > Q.
   4. pKa value of the conjugate acids of the leaving groups in P, Q and R follows the order R > Q > P.

SECTION 3 (Maximum Marks:24)

• This section contains SIX (06) questions.
• The answer to each question is a NON-NEGATIVE INTEGER.
• For each question, enter the correct integer corresponding to the answer using the mouse and the on- screen virtual numeric keypad in the place designated to enter the answer.
• Answer to each question will be evaluated according to the following marking scheme:
  
  • Full Marks: +4 If ONLY the correct integer is entered;
  • Zero Marks: 0 In all other cases.

8. In an electrochemical cell, dichromate ions in aqueous acidic medium are reduced to $Cr^{3+}$. The current (in amperes) that flows through the cell for 48.25 minutes to produce 1 mole of $Cr^{3+}$ is ______.
   Use: 1 Faraday = 96500 $C mol^{−1}$
9. At 25 ℃, the concentration of $H^{+}$ ions in $1.00 × 10^{−3} M$ aqueous solution of a weak monobasic acid having acid dissociation constant $(K_a)$ of $4.00 × 10^{−11}$ is $𝑿 × 10^{−7} M$. The value of $𝑿$ is ______.
   Use: Ionic product of water $(K_w)$ = $1.00 × 10^{−14}$ at 25 ℃
10. Molar volume $(V_m)$ of a van der Waals gas can be calculated by expressing the van der Waals equation as a cubic equation with $V_m$ as the variable. The ratio (in $mol dm^{−3}$) of the coefficient of $𝑉_m^2$to the coefficient of $V_m$ for a gas having van der Waals constants $a = 6.0 dm^6 atm mol^{−2}$ and $b = 0.060dm^3 mol^{−1}$ at 300 $K$ and 300 $atm$ is ______.
    Use: Universal gas constant $(R)$ = $0.082 dm^3 atm mol^{−1} K^{−1}$
11. Considering ideal gas behavior, the expansion work done (in $kJ$) when $144 g$ of water is electrolyzed completely under constant pressure at $300 K$ is ______.
    Use: Universal gas constant ($R$) = $8.3 J K^{−1} mol^{−1}$; Atomic mass (in $amu$): $H$ = 1, $O$ = 16
12. The monomer $(X)$ involved in the synthesis of Nylon 6,6 gives positive carbylamine test. If 10 moles of $X$ are analyzed using Dumas method, the amount (in grams) of nitrogen gas evolved is ______.
    Use: Atomic mass of $N$ (in $amu$) = 14
13. The reaction sequence given below is carried out with 16 moles of $X$. The yield of the major product in each step is given below the product in parentheses. The amount (in grams) of $S$produced is______.
    
    
    
    
    Use: Atomic mass (in $amu$): $H$ = 1, $C$ = 12, $O$ = 16, $Br$ = 80

SECTION 4 (Maximum Marks:12)

• This section contains FOUR (04) Matching List Sets.
• Each set has ONE Multiple Choice Question.
• Each set has TWO lists: List-I and List-II.
• List-I has Four entries (P), (Q), (R) and (S) and List-II has Five entries (1), (2), (3), (4) and (5).
• FOUR options are given in each Multiple Choice Question based on List-I and List-II and ONLY ONE of these four options satisfies the condition asked in the Multiple Choice Question.
• Answer to each question will be evaluated according to the following marking scheme:
  
  • Full Marks: +3 ONLY if the option corresponding to the correct combination is chosen;
  • Zero Marks: 0   If none of the options is chosen (i.e. the question is unanswered);
  • Negative Marks: -1 In all other cases.

14. The correct match of the group reagents in List-I for precipitating the metal ion given in List-II from solutions, is
                                                                                                        

    	List - I		List - II
    (P)	Passing $H_2S$ in the presence of $NH_4OH$	(1)	$Cu^{2+}$
    (Q)	$(NH_4)_2CO_3$ in the presence of $NH_4OH$	(2)	$Al^{3+}$
    (R)	$NH_4OH$ in the presence of $NH_4Cl$	(3)	$Mn^{2+}$
    (S)	Passing $H_2S$ in the presence of dilute $HCl$	(4)	$Ba^{2+}$
    		(5)	$Mg^{2+}$

    
    The correct option is:  
     
    1. P → 3; Q → 4; R → 2; S → 1
       
    2. P → 4; Q → 2; R → 3; S → 1
       
    3. P → 3; Q → 4; R → 1; S → 5
       
    4. P → 5; Q → 3; R → 2; S → 4
15. The major products obtained from the reactions in List-II are the reactants for the named reactions mentioned in List-I. Match each entry in List-I with the appropriate entry in List-II and choose the correct option.                                                                                                  

    	List - I		List - II
    (P)	Stephen reaction	(1)
    (Q)	Sandmeyer reaction	(2)
    (R)	Hoffmann bromamide degradation reaction	(3)
    (S)	Cannizzaro reaction	(4)
    		(5)

    
    The correct option is:  
     
    1. P → 2; Q → 4; R → 1; S → 3
       
    2. P → 2; Q → 3; R → 4; S → 1
       
    3. P → 5; Q → 3; R → 4; S → 2
       
    4. P → 5; Q → 4; R → 2; S → 1
16. Match the compounds in List-I with the appropriate observations in List-II and choose the correct option.                                                                                                     

    	List - I		List - II
    (P)		(1)	Reaction with phenyl diazonium salt gives yellow dye.
    (Q)		(2)	Reaction with ninhydrin gives purple color and it also reacts with $FeCl_3$ to give violet color.
    (R)		(3)	Reaction with glucose will give corresponding hydrazone.
    (S)		(4)	Lassiagne extract of the compound treated with dilute $HCl$ followed by addition of aqueous $FeCl_3$ gives blood red color.
    		(5)	After complete hydrolysis, it will give ninhydrin test and it DOES NOT give positive phthalein dye test.

    
    The correct option is:  
     
    1. P → 1; Q → 5; R → 4; S → 2
       
    2. P → 2; Q → 5; R → 1; S → 3
       
    3. P → 5; Q → 2; R → 1; S → 4
       
    4. P → 2; Q → 1; R → 5; S → 3

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