Haloalkanes and Haloarenes — Chemistry STD 12 Science — Question

Derive a formula to determine the molar mass of a solute by depression of freezing point.

Describe the structure of a fuel cell. Draw labelled diagram of a structure of fuel cell?

How can you remove the hard calcium carbonate layer of the egg without damaging its semiprermiable membrane? Can this egg be inserted into a bottle with a narrow neck without distorting its shape? Explain the process involved.

The rate constant for the first order decomposition of H₂O₂ is given by the following equation:
log k = 14.34 – 1.25 × 10⁴K/T
Calculate E_a for this reaction and at what temperature will its half-period be 256 minutes?

Explain valence bond theory for coordination compounds.

Explain the open chain structure of glucose.

1. Account for the following:

1. Mn₂O₇ is acidic whereas MnO is basic.
2. Though copper has completely filled d-orbital (d¹⁰) yet it is considered as a transition metal.
3. Actinoids show wide range of oxidation states.

2. Write the preparation of potassium permanganate from pyrolusite ore (MnO₂).

Discuss biological and industrial importance of osmosis.

What is meant by stability of a coordination compound in solution? State the factors which govern stability of complexes.

1. The elements of 3d transition series are given as:

Sc Ti V Cr Mn Fe Co Ni Cu Zn

Answer the following:

1. Which element has the highest m.p. and why?
2. Which element is a strong oxidising agent in +3 oxidation state and why?
3. Which element is soft and why?

2. Write the equations involved in the preparation of Potassium dichromate from Sodium chromate (Na₂CrO₄).