Question

17.(b-2b) alkinlarning umumiy formulasini koʻrsating.
a) $\ce{c_{n}h_{2n-2}}$ b) $\ce{c_{n}h_{2n+2}}$ c) $\ce{c_{n}h_{2n}}$ d) $\ce{c_{n}h_{2n-6}}$

18.(b-2b) propilen quyidagi moddalarning qaysilari bilan birikish reaktsiyasiga kirishadi?

1. $\ce{hcl}$;\t\t\t2) $\ce{br_{2}}$(suv);\t\t3) $\ce{kmno_{4}}$(sovuq);
2. $\ce{h_{2}o}$ ($\ce{h_{2}so_{4}}$);\t5) $\ce{cucl}$ ($\ce{nh_{3}}$).

a) 1, 3, 5\tb) 1, 3, 4
c) 2, 3, 5\td) 1, 2, 4

Explanation:

Question 17

Alkynes are unsaturated hydrocarbons with a triple bond between carbon atoms. The general formula for alkynes is derived from the fact that each triple bond reduces the number of hydrogen atoms by 4 compared to alkanes (which have formula \( C_nH_{2n + 2} \)). For alkynes, the formula is \( C_nH_{2n-2} \). Option A is \( C_nH_{2n - 2} \), B is for alkanes, C for alkenes, and D for arenes (like benzene derivatives).

Propylene (\( CH_3CH = CH_2 \)) is an alkene, which undergoes addition reactions. Let's analyze each reagent:

1. \( HCl \): Undergoes electrophilic addition (Markovnikov's rule) with alkenes.
2. \( Br_2 \) (water): Undergoes addition (bromohydrin formation) with alkenes.
3. \( KMnO_4 \) (aqueous): Oxidizes alkenes (breaks the double bond), this is an oxidation, not addition.
4. \( H_2O \) (with \( H_2SO_4 \)): Undergoes acid - catalyzed hydration (addition of water) to form alcohols.
5. \( CuCl(NH_3) \): This reagent is used for the detection of terminal alkynes (to form a red precipitate), not for addition reactions with alkenes.

So the reagents that undergo addition with propylene are 1, 2, 4.

Answer:

A) \( \boldsymbol{C_nH_{2n-2}} \)

Question 18