Explain the following facts

On the other hand gelatin sol is lyophilic in nature and gelatin particles are heavily hydrated and so water envelopes around them and prevents their coming in contact with electrolyte. Hence, it is not easily coagulated on addition of electrolyte. 

The applications of colloids can broadly be divided into three types  

The rubber particles carry a negative charge. When rubber is to be deposited on any material, then two electrodes are made. The anode is made of that substance on which rubber has to be deposited. On passing an electric current, rubber thus deposits on the substance. 

In volumetric analysis, hydrophilic colloids alter the end point, e.g., in a titration of HC1 and NaOH, the amount of deviation in the end point is increased with increasing amounts of colloids. In the volumetric estimation of silver by Mohr s method, the phenomenon of adsorption comes into being. 

In gravimetric analysis, definite crystalline precipitates are desired and the procedure thus adopted aims to get sufficiently bigger particles, because extremely small particles may pass through the filter paper. To prevent adsorption of the undesirable molecules with the desired precipitate, it is necessary to precipitate the solution at the boiling point and fairly dilute solution should be used. 

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Problem 9.49 Explain the following facts in terms of the structure of cyclopropane, a) The H s of cyclopropane are more acidic than those of propane, (b) The Cl of chlorocyclopropane is less reactive toward S. j2 and S l displacements than the Cl in CH3CHCICH3. 

Such a proposal agrees with the general shift toward retention of exocyclic leaving groups. However, it fails to explain the following facts ... 

Exercise 11-5 Use bond energies to explain the following facts ... 

Explain the following facts (a) Copper and iron have several oxidation states, whereas zinc has only one. (b) Copper and iron form colored ions, whereas zinc does not. 

Explain the following facts Treating (Z)-2-butene with OSO4 in pyridine and then NaHSOs in water gives a diol that is optically inactive and cannot be resolved. Treating (. )-2-butene with the same reagents gives a diol that is optically inactive but can be resolved into enantiomers. 

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