(d) Sulphur rhombic(s), can exist sulphur as sulphur monoclinic(s), liquid sulphur(l) and sulphur vapour(g). Maximum number of phases which can coexist in equilibrium can be
(i) 3
(ii) 4
(iii) 1
(iv) 2
(e) The absorbent used for humidity and moisture control in many utility items is
(i) activated charcoal
(ii) silica gel
(iii) metal nanoparticles
(iv) finely divided nickel
2. Answer the following questions :2x5=10
(a) Water and sulphur both are one component system. Water system has one triple point but, sulphur system has more than one triple point in the phase diagram. Explain.
(b) What is critical solution temperature (CST)? Give one example each of solution with lower and upper CST.1+1=2
Describe the Ostwald isolation method for determination of order of a reaction.
(d) Explain the effect of particle size heterogeneous catalysis.
(e) When the adsorbate is adsorbed onto a surface of adsorbent, then both the enthalpy and entropy changes become negative. Explain. 2
3. Answer any two of the following questions 6x2=12
(a)(i) Derive Gibbs phase rule thermodynamically for reactive and non-reactive systems.
4(ii) What are condensed systems? Write phase rule equation for such systems.1+1=2
(i) Melting point of pure Pb is 327 °C and of pure Ag is 961 °C and eutectic point is observed at 303 °C with 97-4% of Pb and 2.6% of Ag. Draw a labelled phase diagram of Pb-Ag system.
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