264. Commercial scale production of hydrogen from iron-steam reaction represented by, 3Fe + 3H₂O = Fe₃O₄ + 4H₂, is not practised, as it is

A slow reaction
A discontinuous reaction (requiring regeneration of iron by water gas intermittently)
Still in development stage (by employing fluidised bed technique)
All of the above
✅ The correct answer is option D.

265. During the manufacture of sulphuric acid, the temperature of molten sulphur is not increased beyond 160°C, as

It is very corrosive at elevated temperature
Its viscosity is not reduced on further heating (hence pressure drop on pumping it, cannot be further reduced)
It decomposes on further increasing the temperature
None of these
✅ The correct answer is option B.