Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

Download the PDF Sample Papers Free for off line practice and view the Solutions online.

ISC Class 12 Chemistry Solved Question Paper 2006

Short Answer Type

11. Correct the following statements :

When tin is treated with cold and very dilute nitric acid, stannic acid is formed.

936 Views

12. Correct the following statements :

Oxidation of sucrose with concentrated nitric acid yields glycerol.

497 Views

13. The depression in the freezing point of a sugar solution was found to be 0.402°C. Calculate the osmotic pressure of the sugar solution at 27°C. (K_f = 1.86 K kg mol^{– 1}

943 Views

14.

A solution is prepared by dissolving 2.0 g of sucrose and 2.0 g of urea in 100 g of water at 298 K. Calculate the vapour pressure of the solution, if the vapour pressure of pure water at 298 K is 23.756 torr.

(Molecular weight of urea = 60 and sucrose = 342)

1441 Views

15.
The average life-period of a radioactive nucleide is 100 hours. How long will it take for 10 g of the nucleide to lose 75 percent of its radioactivity ? [4]

(ii) Calculate the number of α -particles and β-particles emitted in a total transformation from $Th presubscript 90 presuperscript 232 space to space Pb presubscript 82 presuperscript 208$ .

Average space life minus period space straight zeta space equals 1 over straight K straight K space equals 1 over 100 space equals space 0.01 space hr to the power of negative 1 end exponent left square bracket straight N subscript 0 space equals space initial space amount space equals 100 right square bracket comma space left square bracket straight N subscript straight A space equals amount space left space after space time space straight t equals space 25 right square bracket Time space taken space for space decay space equals space straight t equals fraction numerator 2.303 over denominator 0.01 end fraction space log space 100 over 25 space equals space fraction numerator 2.303 over denominator 0.01 end fraction space straight x space log space 4 space equals space 138.65 space hr ii right parenthesis space let space straight x space be space number space of space straight alpha minus particles space and space straight y space be space number space of space 3 minus particles space emitted space during space nuclear space change Th presubscript 90 superscript 232 space rightwards arrow space Pb presubscript 82 superscript 208 space plus straight x subscript 2 He to the power of 4 space plus straight y subscript negative 1 end subscript straight e to the power of 0 straight a right parenthesis space comparing space mass space number 232 space equals space 208 space plus 4 straight x plus 0 4 straight x space equals 232 minus 208 straight x space 24 over 4 space equals space 6 ii right parenthesis space Comparing space atomic space number 90 equals 82 plus 2 straight x minus straight y substituting space value space of space straight x space 90 equals 82 plus 2 space straight x space 6 minus straight y Number space of space straight alpha minus particles space emitted space equals 6 Number space of space straight beta space minus particles space emitted space equals 4

308 Views

16. What is the shape of an acetylene molecule ? Mention the type of hybridization present in it.

352 Views

17. Draw the molecular orbital diagram for O⁺₂ .What is its bond order ? State whether this molecule is paramagnetic or diamagnetic.

330 Views

18. Two ionic compounds AB find AB₂ have the same solubility product. Which of the two compounds has a higher solubility at the same temperature ? Justify your answer.

585 Views