An alkali is titrated against an acid with methyl orange as indicator, which of the following is a correct combination?

• Base	Acid	End Point
  Strong	Strong	Pink to colourless

• Base	Acid	End Point
  Weak	Strong	Colourless to pink

• Base	Acid	End Point
  Strong	Strong	Pinkish Red to Yellow

• Base	Acid	End Point
  Weak	Strong	Yellow to Pinkish Red

The predominant form of histamine present in human blood is (pKa, Histidine = 6.0)

3.

Which of the following lines correctly show the temperature dependence of equilibrium constant K, for an exothermic reaction?

• A and D

• A and B

• B and C

• C and D

The combustion of benzene (l) gives CO₂(g) and H₂O(l). Given that heat of combustion of benzene at constant volume is –3263.9 kJ mol^–1 at 250C; the heat of combustion (in kJ mol^–1) of benzene at constant pressure will be (R = 8.314 JK^–1 mol^–1)

• –3267.6

• 4152.6

• –452.46

• 3260

The ratio of mass percent of C and H of an organic compound (C_XH_YO_Z) is 6: 1. If one molecule of the above compound (C_XH_YO_Z) contains half as much oxygen as required to burn one molecule of compound C_XH_Y completely to CO₂ and H₂O. The empirical formula of compound C_XH_YO_Z is

• C₂H₄O₃

• C₃H₆O₃

• C₂H₄O

• C₃H₄O₂

Which of the following are Lewis acids?

• BCl₃ and AlCl₃

• PH₃ and BCl₃

• AlCl₃ and SiCl₄

• PH₃ and SiCl₄

According to molecular orbital theory, which of the following will not be a viable molecule?

• $H_2^{2-}$

• $H{e}_2^{2+}$

• $H{e}_2^{+}$

• $H_2^{-}$

Which of the following compounds contain(s) no covalent bond(s)?
KCl, PH₃, O2, B₂H₆, H₂SO₄

• KCl, B₂H₆

• KCl, B₂H₆, PH₃

• KCl, H₂SO₄

• KCl

Total number of lone pair of electrons in  I₃^- ion is

• 12

• 3

• 6

• 9

Hydrogen peroxide oxidises $Fe(CN{)}_6{]}^{4-} to [Fe(CN{)}_6{]}^{3-}$ in acidic medium but reduces $\left[Fe\right(CN{)}_6{]}^{3-} to \left[Fe\right(CN{)}_6{]}^{4-}$ in alkaline medium. The other products formed are, respectively

• H₂O and (H₂O + OH^-)

• (H₂O + O₂) and H₂O

• (H₂O + O₂) and (H₂O + OH^-)

• H₂O and (H₂O + O₂)