Réactions acido-basiques : concepts et applications

Question 1 sur 10 10:00

[{"id":46036,"question":"Quel est l'acide conjugué de la base NH₃ ?","option_a":"NH₄⁺","option_b":"NH₂⁻","option_c":"H₂O","option_d":"OH⁻","option_e":"","option_f":"","bonne_reponse":"A","explication":"La base NH₃ accepte un proton H⁺ pour former son acide conjugué NH₄⁺.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":46037,"question":"Une solution a un pH de 3. Elle est :","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"A","explication":"Un pH inférieur à 7 indique une solution acide.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":46038,"question":"Quelle est la formule du pH en fonction de la concentration en ions H₃O⁺ ?","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":"La formule correcte est pH = -log[H₃O⁺], où [H₃O⁺] est en mol\/L.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":46039,"question":"Dans la réaction HCl + H₂O → H₃O⁺ + Cl⁻, l'eau joue le rôle de :","option_a":"Acide","option_b":"Base","option_c":"Solvant","option_d":"Catalyseur","option_e":"","option_f":"","bonne_reponse":"B","explication":"L'eau accepte un proton H⁺ pour former H₃O⁺, elle se comporte donc comme une base.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":46040,"question":"Une solution de soude (NaOH) a un pH de 12. Sa concentration en ions OH⁻ est :","option_a":"10⁻¹² mol\/L","option_b":"10⁻² mol\/L","option_c":"10⁻⁷ mol\/L","option_d":"10⁻¹⁴ mol\/L","option_e":"","option_f":"","bonne_reponse":"B","explication":"pH = 12 ⇒ pOH = 2 ⇒ [OH⁻] = 10⁻² mol\/L.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":46041,"question":"La réaction entre un acide et une base produit toujours de l'eau.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"B","explication":"La réaction produit de l'eau uniquement si l'acide et la base sont forts. Avec des espèces faibles, d'autres produits peuvent se former.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":46042,"question":"Quel est le pH d'une solution de HCl de concentration 10⁻³ mol\/L ?","option_a":"3","option_b":"11","option_c":"-3","option_d":"1","option_e":"","option_f":"","bonne_reponse":"A","explication":"HCl est un acide fort qui se dissocie totalement : [H₃O⁺] = 10⁻³ ⇒ pH = 3.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":46043,"question":"Dans le couple CH₃COOH\/CH₃COO⁻, CH₃COOH est :","option_a":"La base","option_b":"L'acide","option_c":"Le solvant","option_d":"Le catalyseur","option_e":"","option_f":"","bonne_reponse":"B","explication":"CH₃COOH peut céder un proton H⁺ pour former CH₃COO⁻, c'est donc l'acide du couple.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":46044,"question":"Une solution a un pH de 8. Elle est :","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"B","explication":"Un pH supérieur à 7 indique une solution basique.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":46045,"question":"Quelle est l'équation de neutralisation entre HCl et NaOH ?","option_a":"HCl + NaOH → NaCl + H₂O","option_b":"HCl + NaOH → Na⁺ + Cl⁻ + H₂O","option_c":"HCl + NaOH → NaCl","option_d":"HCl + NaOH → H₂ + NaCl","option_e":"","option_f":"","bonne_reponse":"A","explication":"La réaction de neutralisation produit du chlorure de sodium (NaCl) et de l'eau (H₂O).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0}]