#### 12th Standard English Medium Chemistry Reduced Syllabus Five mark Important Questions - 2021(Public Exam )

12th Standard

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Chemistry

Time : 02:00:00 Hrs
Total Marks : 125

Part A

25 x 5 = 125
1. The selection of reducing agent depends on the thermodynamic factor: Explain with an example.

2. In the extraction of copper, explain the smelting process.

3. How are silicates classified? Give an example for each type of silicate.

4. What happens when PCl5 is heated?

5. Mention the uses of helium

6. How is sulphuric acid manufacture by contact process?

7. Out of Lu(OH)3 and La(OH)3 which is more basic and why?

8. Predict which of the following will be coloured in aqueous solution Ti2+ , V3+ Sc4+, Cu+ ,Sc3+, Fe3+, Ni2+ and Co3+

9. Write a short note on the oxidation states of 3d series elements.

10. What is crystal field splitting energy?

11. How are metal carbonyls classified depending on the number of metal atoms?

12. KF crystallizes in fcc structure like sodium chloride. calculate the distance between K+ and F in KF.( given : density of KF is 2483. gcm-3)

13. The half life of the homogeneous gaseous reaction SO2Cl2 → SO2 + Cl2 which obeys first order kinetics is 8.0 minutes. How long will it take for the concentration of SO2Cl2 to be reduced to 1% of the initial value?

14. For the reaction 2A + B ⟶ A2B. The rate = k [A] [B]2 with k = 2.0 x 10-6 mol? L2 S-1. Calculate the initial rate of the reaction, when [A] = 0.1 mol L-1, [B] = 0.2 mol L-1. Calculate the rate of reaction after [A] is reduced to 0.06 mol L-1

15. Rate constant of a first order reaction is 0.45 sec-1, calculate its half life.

16. Write the expression for the solubility product of Ca3 (PO4)2

17. If a solution has a pH of 7.41, determine its H+ concentration.

18. On hydrolysis of salts of strong acid and strong base, the solution obtained is neutral. Justify your answer with a suitable example

19.  Calculate the standard emf of the cell: Cd|Cd2+||Cu2+|Cu and determine the cell reaction. The standard reduction potentials of Cu2+|Cu and Cd2+|Cd  are 0.34V and -0.40 volts respectively. Predict the feasibility of the cell reaction.

20. Explain any one method for coagulation

21. How will you convert acetylene into n-butyl alcohol.

22. Complete the following reaction
${ CH }_{ 3 }-{ CH }_{ 2 }-{ CH }_{ 2 }-\underset { \overset { || }{ O } }{ C } -{ CH }_{ 3 }\overset { HO-{ CH }_{ 2 }-{ CH }_{ 2 }-OH }{ \underset { { dry }{ HCl} }{ \longrightarrow } } ?$

23. A Monoobromoderivative (A) on treatment with KCN followed by acid hydrolysis and heating gives a monobasic acid (B) along with liberation of CO2 . (B) on heating with liquid ammonia followed by treating with Br2 /KOH  gives (c) which on treating with NaNO2 and HCl at low temperature followed by oxidation gives a monobasic acid (D) having molecular mass 74. Identify A to D.

24. Writhe the structure of α-D (+) glucophyranose

25. Write a note on co –polymer