Les réactions acido-basiques : concepts et applications

Question 1 sur 10 10:00

[{"id":59137,"question":"Selon Brønsted-Lowry, un acide est une espèce chimique capable de :","option_a":"Céder un proton H+","option_b":"Capter un proton H+","option_c":"Céder un électron","option_d":"Capter un électron","option_e":"","option_f":"","bonne_reponse":"A","explication":"Un acide de Brønsted-Lowry est une espèce qui cède un proton H+ (définition de Brønsted-Lowry).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":59138,"question":"Le pH d'une solution est égal à 7. Cette solution est :","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"B","explication":"Une solution de pH = 7 est neutre. Le pH \u003C 7 indique une solution acide, et le pH \u003E 7 une solution basique.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":59139,"question":"Quel est le couple acido-basique correspondant à l'acide chlorhydrique (HCl) ?","option_a":"HCl\/Cl-","option_b":"H3O+\/H2O","option_c":"H2O\/OH-","option_d":"NH4+\/NH3","option_e":"","option_f":"","bonne_reponse":"A","explication":"L'acide chlorhydrique (HCl) cède un proton pour former son ion conjugué Cl-.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":59140,"question":"La réaction entre l'acide sulfurique (H2SO4) et l'eau (H2O) produit :","option_a":"H3O+ et SO4^2-","option_b":"H2O et SO4^2-","option_c":"H3O+ et HSO4-","option_d":"OH- et HSO4-","option_e":"","option_f":"","bonne_reponse":"C","explication":"H2SO4 + H2O → H3O+ + HSO4- (première dissociation de l'acide sulfurique).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":59141,"question":"Une solution de soude (NaOH) a un pH de 13. Cette solution est :","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"A","explication":"Une solution de pH = 13 est basique (pH \u003E 7). La soude (NaOH) est une base forte.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":59142,"question":"Quelle est la formule du pH ?","option_a":"pH = -log[H3O+]","option_b":"pH = log[H3O+]","option_c":"pH = [H3O+]","option_d":"pH = 1\/[H3O+]","option_e":"","option_f":"","bonne_reponse":"A","explication":"Le pH est défini par la formule pH = -log[H3O+], où [H3O+] est la concentration en ions oxonium.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":59143,"question":"La neutralisation d'un acide par une base produit toujours :","option_a":"De l'eau et un sel","option_b":"Un gaz","option_c":"Un précipité","option_d":"Un acide plus fort","option_e":"","option_f":"","bonne_reponse":"A","explication":"La réaction de neutralisation entre un acide et une base donne de l'eau et un sel (ex : HCl + NaOH → NaCl + H2O).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":59144,"question":"Le papier pH permet de mesurer la concentration en ions H3O+.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"B","explication":"Le papier pH indique la valeur du pH, mais ne mesure pas directement la concentration en ions H3O+.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":59145,"question":"Quel est le pH d'une solution de concentration [H3O+] = 10^-3 mol\/L ?","option_a":"pH = 3","option_b":"pH = 11","option_c":"pH = -3","option_d":"pH = 0,001","option_e":"","option_f":"","bonne_reponse":"A","explication":"pH = -log[10^-3] = 3. Une concentration élevée en H3O+ correspond à un pH acide.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":59146,"question":"La réaction entre l'acide acétique (CH3COOH) et l'eau est une réaction totale.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"B","explication":"L'acide acétique est un acide faible : sa réaction avec l'eau est partielle (équilibre chimique).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0}]