[" 6.a) Define collosien - "],[" b) What is coserosion of isom called? "],[" c) How hill you lecognise res cosecosen "],[" silver? "],[" d) Why cossasion of erow is a serious pro "],[" e) Holw can we prevent cossasion? "]

(i) Define corrosion . (ii) What is corrosion of iron called? (iii) How will you recognise the corrosion of silver? (iv) Why corrosion of iron is a serious problem ?

a. Define corrosion. b. What is corrosion of iron called? c.Why corrosion of ironis a serious problem? d. How we can prevent corrosion of iron? e. How will you recognise the corrosion of silver? OR Why does silver turn blackish when exposed to air?

(a) Define corrosion, what is the nature given to corrosion of iron ? (b) Name the colour of coating formed on silver and copper when exposed to air. (c ) List two damages caused by corrosion and suggest, how these can be prevented.

Tincture of iodine is a mixture of two materials X and Y. The material Y has a property that its solid from can be convertyed directly into vapours on heating by a process called Z. (a) What coluld X be ? (b) What could Y be ? (c ) Name the process Z. (d) Which process would you use to recover both the components X and Y from tincture of iodine ? (e) Which process can be used to recover only, component Y from tincture of iodine ?

In an experiment to estimate the size of a molecule of oleic acid 1 mL of oleic acid is dissolved in 19 ml of alcohol. Then I mL of this solution is diluted to 20 mL by adding alcohol. Now 1 drop of this diluted solution is placed on water in a shallow through. The solution spreads over the surface of water forming one molecule thick layer. Now lycopodium powder is sprinkled evenly over the film and its diameter is measured. Knowing the volume of the drop and area of the film we can calculate the thickness of the film which will give us the size of oleic acid molecule. Read the passage carefully and answer the following questions. (a) Why do we dissolve oleic acid in alcohol ? (b) What is the role of lycopodium powder ? (c) What would be the volume of oleic acid in each ml of solution prepared ? (d) How will you calculate the volume of n drops of this solution of oleic acid ? (e) What will be the volume of oleic acid in one drop of this solution ?

In an experiment to estimate the size of a molecule of oleic acid 1 mL of oleic acid is dissolved in 19 mL of alcohol. Then 1 mL of this solution is diluted to 20 mL by adding alcohol. Now, 1 drop of this diluted solution is placed on water in a shallow trough. The solution spreads over the surface of water forming one molecule thick layer. Now, lycopodium powder is sprinkled evenly over the film and its diameter is measured. Knowing the volume of the drop and area of the film we can calculate the thickness of the film which will give us the size of oleic acid molecule. Read the passage carefully and answer the following questions (a) Why do we dissolve oleic acid in alcohol ? (b) What is the role of lycopodium powder? (c) What would be the volume of oleic acid in each mL of solution prepared? (d) How will you calculate the volume of n drops of this solution of oleic acid ? (e) What will be the volume of oleic acid in one drop of this solution ?

a. When we look through a muslin cloth,we can see coloured spectrum. How will you explain this? b. Observe the shadow of your book when it is held a few centrimeters above as table with a lamp serveral centimeter above the book. Why is the shadow the book fuzzy at the edges? c.If you observe a distant street light between two fringers pinched together, you can visualise alternate bright and dark fringes. What is this due to? Explain.