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Model Paper 8 — Chemistry STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceChemistryModel Paper 85 Marks
Question
Attempt any five of the following:
1. What effect does branching of an alkene chain has on its boiling point?
2. What are Arenes?
3. Write IUPAC name of the following: $CH _3\left( CH _2\right)_4 CH \left( CH _2\right)_3 CH _3 CH _2- CH \left( CH _3\right)_2$
4. Why are alkanes called paraffins?
5. State Le chatelier's principle.
6. What is decarboxylation? Give an example.
7. Arrange the following: $HCl , HBr , Hl , HF$ in order of decreasing reactivity towards alkenes.
✓

Answer

1. Branching of carbon atom chain decreases the boiling point of alkane.
2. Arenes are aromatic hydrocarbons
3. The IUPAC name of given compound is:

4. Paraffins means little affinity. Alkanes due to strong C-C and C-H bonds are relatively chemically inert.
5. Le chatelier's principle: If a system at equilibrium is subjected to change in the temperature, pressure or concentration of the reactants or the products that govern the equilibrium, then the equilibrium shifts in that direction in which this change is reduced or nullified.
6. The process by which carbon dioxide is removed from sodium acetate (or any sodium salt of acid) with the help of sodalime is called decarboxylation.
Image
7. $HI> HBr > HCl > HF$

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