15. Halogen compounds
A section of Chemistry, 9701
Listing 10 of 284 questions
The substituted benzene compound can be further substituted. If Y is an electron-withdrawing group, the next substitution will be in position 3. If Y is an electron-releasing group, the next substitution will be mostly in position 4. X + X if Y is electron-withdrawing + X if Y is electron-releasing Y Y Y X The following table lists some electron-withdrawing and electron-releasing substituents. electron-withdrawing groups electron-releasing groups –NO2 –CH3 –COCH3 –CH2Br –CO2H –NH2 Use the above information to draw relevant structural formulae in the boxes in the schemes below. CH3 H+ KMnO4 + OH– H+ KMnO4 + OH– OH– Sn + HCl Br2 + Al Cl 3 E D C B A HNO3 + H2SO4
9701_s08_qp_4
THEORY
2008
Paper 4, Variant 0
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Some transition element complexes can show stereoisomerism. State two types of stereoisomerism shown by transition element complexes. The complexes [Pt(NH3)2Cl2] and 2+ have the same geometry around the metal ion. [Pt(NH3)2Cl2] exists as two stereoisomers whereas 2+ only has one possible structure. State the geometry around the metal ion. The complex 2+ exists as two stereoisomers whereas the complex [Cr(OCH2CH2NH2)3 ]− exists as four stereoisomers. Complete the three‑dimensional diagrams in to show the four stereoisomers of [Cr(OCH2CH2NH2)3 ]−. Represent the ligand –OCH2CH2NH2 by using O N . Cr Cr Cr Cr The complex [Cr(OCH2CH2NH2)3]− is formed by reacting Cr 2+with the conjugate base of 2‑aminoethanol. A synthesis of 2‑aminoethanol is shown in . oxirane 2-aminoethanol H H H H2N + NH3 OH C O C H Suggest the mechanism for step 1 of the reaction of oxirane with ammonia in . Include all relevant curly arrows, lone pairs of electrons, charges and partial charges. Draw the structure of the organic intermediate. intermediate oxirane 2-aminoethanol step 1 step 2 H H H H3N H2N OH C O C H A small amount of by‑product E, shown in , is produced during the reaction shown in . E N H OH HO Suggest how the formation of by‑product E can be minimised. Compound F, C4H9NO, can be formed from the reaction of by‑product E, C4H11NO2, with concentrated H2SO4. Compound F is a saturated and basic organic compound. Suggest a structure for compound F. State the type of reaction undergone by E to form F. F type of reaction
9701_s23_qp_41
THEORY
2023
Paper 4, Variant 1
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Some transition element complexes can show stereoisomerism. State two types of stereoisomerism shown by transition element complexes. The complexes [Pt(NH3)2Cl2] and 2+ have the same geometry around the metal ion. [Pt(NH3)2Cl2] exists as two stereoisomers whereas 2+ only has one possible structure. State the geometry around the metal ion. The complex 2+ exists as two stereoisomers whereas the complex [Cr(OCH2CH2NH2)3 ]− exists as four stereoisomers. Complete the three‑dimensional diagrams in to show the four stereoisomers of [Cr(OCH2CH2NH2)3 ]−. Represent the ligand –OCH2CH2NH2 by using O N . Cr Cr Cr Cr The complex [Cr(OCH2CH2NH2)3]− is formed by reacting Cr 2+with the conjugate base of 2‑aminoethanol. A synthesis of 2‑aminoethanol is shown in . oxirane 2-aminoethanol H H H H2N + NH3 OH C O C H Suggest the mechanism for step 1 of the reaction of oxirane with ammonia in . Include all relevant curly arrows, lone pairs of electrons, charges and partial charges. Draw the structure of the organic intermediate. intermediate oxirane 2-aminoethanol step 1 step 2 H H H H3N H2N OH C O C H A small amount of by‑product E, shown in , is produced during the reaction shown in . E N H OH HO Suggest how the formation of by‑product E can be minimised. Compound F, C4H9NO, can be formed from the reaction of by‑product E, C4H11NO2, with concentrated H2SO4. Compound F is a saturated and basic organic compound. Suggest a structure for compound F. State the type of reaction undergone by E to form F. F type of reaction
9701_s23_qp_43
THEORY
2023
Paper 4, Variant 3
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