No of C=C bond in carbonyl compound

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Discussion Overview

The discussion revolves around determining the possible structural formula of a carbonyl compound based on its composition by mass and its reactions. Participants analyze the implications of the given data, particularly focusing on the number of C=C bonds in the compound.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant states that the compound X has a composition of 64.3% carbon, 7.1% hydrogen, and 28.6% oxygen, and presents two structural formula options: CH2=CH-CHO and CH3-CH=CH-CH=CH-COH.
  • The same participant argues that based on the reaction with hydrogen gas, there should be two C=C bonds, leading to the conclusion that CH3-CH=CH-CH=CH-COH is the correct structure.
  • Another participant asserts that only one of the two compounds fits the given data, but does not specify which one.
  • Further replies question the correctness of the initial claims and suggest finding the experimental formula or percent elemental compositions from the given formulas.
  • One participant calculates the ratio of C:H:O as 3:4:1 based on the percentages provided.

Areas of Agreement / Disagreement

Participants express differing views on which structural formula is correct, with no consensus reached on the number of C=C bonds or the appropriate structural representation of compound X.

Contextual Notes

Participants have not resolved the assumptions regarding the calculations of the molecular formula or the implications of the elemental composition percentages. The discussion remains focused on interpretations of the data provided.

somecelxis
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Homework Statement




Compound X has the following composition by mass : carbon(64.3%) , 7.1% of hydrogen and oxygen (28.6%) . X reduces Fehling's solution to CuO . Copper( I) oxide .0.1 mol of X react with 4480cm3 of hydrogen gas in the presence of nickel catalyst. What 's the possible structural formula of X ?
there are 2 choices ..
CH2=CH-CHO
CH3-CH=CH-CH=CH-COH

THE ANS IS CH2=CH-CHO ...Why ? can anyone explain on this? thanks in advance!


Homework Equations





The Attempt at a Solution


mol of hydrogen gas = 4480/22400= 0.2 mol

if there's only one C=C bond , then 1 mol of X react with 1 mol of H2 gas ..

But 0.1 mol of X react with 0.2 mol H2 gas , so there are 2 C=C bond in X ... my choice would be CH3-CH=CH-CH=CH-COH ...
but the correct ans is CH2=CH-CHO
 
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somecelxis said:
carbon(64.3%) , 7.1% of hydrogen and oxygen (28.6%)

No idea about everything else, but of the two compounds given only one fits.
 
Borek said:
No idea about everything else, but of the two compounds given only one fits.

so which one is correct?
 
somecelxis said:
so which one is correct?

Have you tried to find the experimental formula from the numbers given? Or even simpler - have you tried to find the percent elemental compositions from the given formulae?
 
Borek said:
Have you tried to find the experimental formula from the numbers given? Or even simpler - have you tried to find the percent elemental compositions from the given formulae?

i got ratio of ratio of C:H:O = 3:4:1
using precentage
 

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