Quiz : Maîtrisez le pH et ses applications en chimie

Question 1 sur 10 10:00

[{"id":10173,"question":"Quel est le pH d'une solution dont la concentration en ions H3O+ est de 10^-3 mol\/L ?","option_a":"pH = 3","option_b":"pH = -3","option_c":"pH = 11","option_d":"pH = 14","option_e":"","option_f":"","bonne_reponse":"A","explication":"Le pH se calcule avec la formule pH = -log[H3O+]. Ici, pH = -log(10^-3) = 3.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":10174,"question":"Une solution de pH = 8 est-elle acide, basique ou neutre ?","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"B","explication":"Une solution de pH = 8 est basique car son pH est supérieur à 7.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":10175,"question":"Quel indicateur coloré devient bleu en milieu basique ?","option_a":"Phénolphtaléine","option_b":"Bleu de bromophénol","option_c":"Hélianthine","option_d":"Bleu de thymol","option_e":"","option_f":"","bonne_reponse":"A","explication":"La phénolphtaléine est incolore en milieu acide et devient rose\/rouge en milieu basique.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":10176,"question":"Si une solution a un pH = 2, quelle est sa concentration en ions H3O+ ?","option_a":"10^-2 mol\/L","option_b":"10^-12 mol\/L","option_c":"10^2 mol\/L","option_d":"10^-7 mol\/L","option_e":"","option_f":"","bonne_reponse":"A","explication":"pH = -log[H3O+] ⇒ [H3O+] = 10^-pH = 10^-2 mol\/L.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":10177,"question":"Le pH d'une solution peut-il être négatif ?","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"A","explication":"Oui, si la concentration en H3O+ est supérieure à 1 mol\/L, le pH peut être négatif.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":10178,"question":"Quelle est la couleur de la solution si on ajoute de la phénolphtaléine dans une solution de pH = 9 ?","option_a":"Incolore","option_b":"Rose","option_c":"Bleu","option_d":"Jaune","option_e":"","option_f":"","bonne_reponse":"B","explication":"La phénolphtaléine devient rose en milieu basique (pH \u003E 8,2).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":10179,"question":"Le pH d'une solution neutre est toujours égal à 7.","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"A","explication":"À 25°C, le pH d'une solution neutre est égal à 7. Cette valeur peut varier avec la température.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":10180,"question":"Quelle formule permet de calculer la concentration en ions OH- à partir du pH ?","option_a":"[OH-] = 10^(pH-14)","option_b":"[OH-] = 10^pH","option_c":"[OH-] = 10^(-pH)","option_d":"[OH-] = pH","option_e":"","option_f":"","bonne_reponse":"A","explication":"On utilise la relation [H3O+][OH-] = 10^-14 ⇒ [OH-] = 10^(pH-14).","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":10181,"question":"Une solution de pH = 5 est-elle plus acide qu'une solution de pH = 3 ?","option_a":"Vrai","option_b":"Faux","option_c":"","option_d":"","option_e":"","option_f":"","bonne_reponse":"B","explication":"Plus le pH est bas, plus la solution est acide. pH = 3 est plus acide que pH = 5.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0},{"id":10182,"question":"Quel est le pH d'une solution de soude (NaOH) à 0,01 mol\/L ?","option_a":"pH = 2","option_b":"pH = 12","option_c":"pH = 7","option_d":"pH = 10","option_e":"","option_f":"","bonne_reponse":"B","explication":"NaOH est une base forte : [OH-] = 0,01 mol\/L ⇒ pOH = 2 ⇒ pH = 14 - pOH = 12.","points":1,"type":"qcm","actif":1,"section_id":null,"ordre":0}]