Ellingham diagrams are plots of ΔGº vs temperature which have applications in metallurgy

2H₂ + O₂ = 2H₂O ΔG(J) = –247500 +55.85 T …….. (I)

2CO + O₂ = 2CO₂ ΔG(J) = –282400 +86.81 T………. (II)

The Ellingham diagrams for the oxidation of H₂(I) and CO (II) are given below.

The two lines intersect (T_E) at 1125 K.

Which of the following is correct ?

I. Δ Gº for reaction (i) is more negative at T < 1125K

II. Δ G° for the reduction of CO is more negative at T < 1125 K

III. H₂ is a better reducing agent at T > 1125 K

IV. H₂ is a better reducing agent at T < 1125 K

(A) I and II 

(B) I and III 

(C) III only 

(D) I and IV

Which of the following cannot act as an oxidising agent ? 

(A) S^2– 

(B) Br₂ 

(C) HSO^–₄ 

(D) 2SO₃

The colour changes of an indicator HIn in acid base titrations is given below

HIn (aq)⇋ H⁺ (aq) + In^– (aq)

Colour X Colour Y

Which of the following statements is correct? 

(A) In a strong alkaline solution colour Y will be observed 

(B) In a strong acidic solution colour Y will be observed 

(C) Concentration of in^– is higher than that of HIn at the equivalence point 

(D) In a strong alkaline solution colour X is observed

The complex ion that does not have d electrons in the metal atom is

(A) [MnO₄]^–

(B) [Co(NH₃)₆]³⁺

(C) [Fe(CN)₆]^3–

(D) Cr(H₂O)₆]³⁺

Which of the following has the shortest bond length? 

(A) O₂ 

(B) O^–₂

(C) O⁺₂

(D) O^-2₂