Quiz — Série_1_Equilibre acide_base_(17-01-2023).pdf

Question 1 sur 10 20:00

[{"id":14569,"question":"Quel est l'acide conjugué de la base NH3 ?","option_a":"NH4+","option_b":"H2O","option_c":"OH-","option_d":"HCl","option_e":"","option_f":"","bonne_reponse":"a","explication":"L'acide conjugué de NH3 (ammoniac) est NH4+ (ion ammonium), obtenu en ajoutant un proton (H+) à NH3.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"NH4+\", \"b\": \"H2O\", \"c\": \"OH-\", \"d\": \"HCl\"}}","_debug_options_count":4},{"id":14570,"question":"Le pH d'une solution de HCl à 0,01 mol\/L est égal à 2.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Le pH se calcule par pH = -log[H3O+]. Pour [HCl] = 0,01 mol\/L, [H3O+] = 0,01 mol\/L, donc pH = -log(0,01) = 2.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":14571,"question":"Quelle est la constante d'acidité (Ka) d'un acide faible HA si [H3O+] = 10^-3 mol\/L et [A-] = 10^-3 mol\/L dans une solution de concentration initiale 0,1 mol\/L ?","option_a":"10^-2","option_b":"10^-3","option_c":"10^-4","option_d":"10^-5","option_e":"","option_f":"","bonne_reponse":"b","explication":"Ka = [H3O+][A-]\/[HA] = (10^-3 * 10^-3)\/(0,1 - 10^-3) ≈ 10^-5. La valeur la plus proche est 10^-5.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"10^-2\", \"b\": \"10^-3\", \"c\": \"10^-4\", \"d\": \"10^-5\"}}","_debug_options_count":4},{"id":14572,"question":"Une solution tampon peut être préparée en mélangeant un acide faible et sa base conjuguée.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Une solution tampon est effectivement composée d'un acide faible et de sa base conjuguée (ou d'une base faible et de son acide conjugué) pour résister aux variations de pH.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":14573,"question":"Quel est le pH d'une solution de NaOH à 0,001 mol\/L ?","option_a":"3","option_b":"11","option_c":"7","option_d":"13","option_e":"","option_f":"","bonne_reponse":"b","explication":"NaOH est une base forte : [OH-] = 0,001 mol\/L. pOH = -log(0,001) = 3. pH = 14 - pOH = 11.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"3\", \"b\": \"11\", \"c\": \"7\", \"d\": \"13\"}}","_debug_options_count":4},{"id":14574,"question":"La constante d'acidité (Ka) d'un acide fort est toujours supérieure à 1.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Un acide fort est totalement dissocié en solution, donc Ka \u003E\u003E 1. Par exemple, Ka pour HCl est très grand.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":14575,"question":"Quelle est la concentration en ions H3O+ dans une solution de pH = 4 ?","option_a":"10^-4 mol\/L","option_b":"10^-10 mol\/L","option_c":"10^4 mol\/L","option_d":"10^-6 mol\/L","option_e":"","option_f":"","bonne_reponse":"a","explication":"Le pH est défini par pH = -log[H3O+]. Donc [H3O+] = 10^-pH = 10^-4 mol\/L.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"10^-4 mol\/L\", \"b\": \"10^-10 mol\/L\", \"c\": \"10^4 mol\/L\", \"d\": \"10^-6","_debug_options_count":4},{"id":14576,"question":"Une solution de CH3COOH (acide acétique) et de CH3COONa (acétate de sodium) forme une solution tampon.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"CH3COOH est un acide faible et CH3COO- (de CH3COONa) est sa base conjuguée. Ce mélange forme bien une solution tampon.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4},{"id":14577,"question":"Quel est le pH d'une solution de HCl à 0,1 mol\/L ?","option_a":"1","option_b":"2","option_c":"3","option_d":"0,1","option_e":"","option_f":"","bonne_reponse":"b","explication":"HCl est un acide fort : [H3O+] = 0,1 mol\/L. pH = -log(0,1) = 1.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"b\", \"options\": {\"a\": \"1\", \"b\": \"2\", \"c\": \"3\", \"d\": \"0,1\"}}","_debug_options_count":4},{"id":14578,"question":"La constante de basicité (Kb) d'une base faible est toujours inférieure à 1.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"a","explication":"Une base faible ne se dissocie que partiellement en solution, donc Kb \u003C 1. Par exemple, Kb pour NH3 est faible.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0,"_debug_answer_data_type":"string","_debug_answer_data_preview":"{\"correct\": \"a\", \"options\": {\"a\": \"Vrai\", \"b\": \"Faux\", \"c\": \"\", \"d\": \"\"}}","_debug_options_count":4}]