What precautions are necessary while purifying an organic solid with the help of cystallisation process ?

Which is not used to purify organic solids ?

Distinguish between esterification and saponification reactions of organic compounds with the help of the chemical equation for each. Write one use of (i) esters and (ii) saponification process?

What precaution would you take to detect the presence of a halogen in an organic compound by Lassaigne's test if the compound contains nitrogen or sulphur also ?

(a) What is fragmentation in organisms? Name a multicellular organism which reproduces by this method. (b) What is regeneration in organisms? Describe regeneration in Planaria with the help of a suitable diagram.

A student was asked by his teacher to separate an impure sample of sulphur containing sand as the impurity. He tried to purify it with the help of sublimation. But he was not successful. Particles of sulphur of sulphur could not be separated completely from sand. (i) Why did the sublimation process succeed ? (ii) Suggest an alternate method to affect the separation. (iii) What is the value based information associated with this ?

(a) List the different attributes that a population has and not an individual organism. (b) What is population density? Explain any three different ways the population density can be measured with the help of an example each.

Benzoic acid is an organic compound. Its crude sample can be purified by crystallisation from hot water. What characeteristic difference in the properties of benzoic acid and the impurity make this process of purification suitable ?

Explain the process of secondary growth in the stems of woody angiosperms with the help of schematic diagrams. What is its significance?

Passage : Post office is useful to measure the value of unknown resistance correctly upto 2nd decimal place. It is based on Wheatstone bridge. Systematic diagrams of post office box are shown in the above figures. Each of the arms AB and BC contains three resistance of 10 Omega, 100 Omega and 1000 Omega . These arms are generally known as ratio arms. With the help of these resistance, we can introduce resistance P in arm AB and Resistance Q in arm BC. The resistance arm AD is complete resistance box containing resistance from 1 Omega "to" 5000 Omega . In this arm, we can introduced resistance R by taking out plugs of suitable values. The unknown resistance X is connected in fourth arm CD. These four arms actually form Wheatstone bridge shown in figure. For balanced conditions, no deflection is formed in galvanometer. At balanced condition PX= QR , X= (QR)/( P) While measuring surface tension of water using capillary rise method the necessary precaution to be taken is/are

While solving logarithmic equations or logarithmic inequalities care must be taken to ensure that the value of the variable obtained do indeed satisfy the given equation . Often the solution consists in transforming the original equation to form which can be solved with ease . But in bargain the process the transformations carried out are not always equivalent .In what follows one must verify that the values of variables obtained indeed satisfy original equation or inequation. How many solutions in real numbers does the equation 3^(x) 8 ^((x)/(x-2)) = 6 have ? i) None ii) Exactly one iii) Exactly two iv) Infinite