C. b anot xayra sir oxi hoa: Cu > C u^^+2e
Huong dan gid i^
- Dung dich CuCK: CuClj -> Cu"^ + 2C\'
Cu^^ + H20<:± C u ( O H f +
' ' C u C l 2- > Cu i + C I 2 t
=> pH trirdc va sau dien phan thay doị - Dung dich AgNO,:
4 A g N 0 3 + 2 H 2 O4 A g + 4 H N O 3 + O2
=> pH thay doị
- Dung dich NaNO,: 2 H 2 O 2H2 + O2
=> pH kh6ng thay d6i
, - Dung dich HCI: 2HCI -> H2 + CI2
=> pH thay doị Rap an diing la C.
11. Dien phan dien circ trodung dich chiia 0,2 mol A g N O , vdi cirdng do dong dien
2,68 A, trong thdi gian t gid thu dugc dung dich X (hieu suat qua trinh dien phan la 100%). Cho 16,8 gam bot Fe vao X tháy thoat ra khi N O (san phiim khir duy nhat) va sau cac phan i/ng hoan toan thu dugc 22,7 gam chat rSn. Gia trj ciia t la Ạ 2,00 B. 1,00 C.0,50 D. 0,25
' Huong dan gidi
T h e o b a i r a : - 16,8/56 = 0,3(mol)
V i khoi Iirgng chat rdn Idn hon khdi lugng Fe nen AgNO, con du sau khi dien phan.
2 A g N 0 3 + H 2 O- > 2Ag i + 2 H N O 3 + ^ 0 3 !
X - > X x ( m o l )
=> Trong dung dich X cd x mol HNO, va (0,2 - x) mol AgNO,. Gia sir k i m loai Fe het thi chat riin la A g
n^j, = 22,7/108 = 0,21mol > n^p,sj(,^ r=> v6 lỵ Vay k i m loai Fe con d u D o d o :
Fe + 2 A g N 0 3 -> F e ( N 0 3 ) , + 2 A g i
0 , 5 . ( 0 , 2 - x ) < - ( 0 , 2 - x ) -> ( 0 , 2 - x ) m o l 3Fe + 8 H N 0 3 ^ 3 F e ( N 0 3 ) 2+ 2 N O + 4 H 2 O
3 x / 8 ^ x (mol)
Chat rdn gom: (0,2 - x) molAg .. , va 0 , 3 - 0 , 5 . ( 0 , 2 - x ) - 3 x / 8 = (l,6 + x)/8molFe
Theo bai ra, ta cd: (0,2 - x ) . 108 +56.(1,6+ x ) / 8 - 2 2 , 7
=> 2 1, 6 - 1 0 8 x + 11,2 + 7x = 22,7 =^ lOlx - 101 =^ X = 0,1
n'.n.F 0,1.1.96500 x , ^. . . . .
V a y t = = - =^1,00(h) Dap an dung la B.
1.3600 2,68.3600 ^ '
12. Tien hanh dien phan (vdi dien circ tro) V lít dung dich CuCl, 0,5M. Khi dirng
dien phan thu dugc dung djch X va 1,68 lit khi CK (dktc) duy nhat d anot. Toan b6 dung dich X tac diing vira dii vdi 12,6 gam Fẹ Gia tri ciia V la
Ạ 0,45. B. 0,80. C.0,60. D.0,15.
Huong dan gidi ^
Theobaira: n ^ , = 0,075inol;np,. = 0,225mol
CUCI2 -> CU + CI2 0,075 <- 0,075 CuClj + Fe ^ F e C l j + C u 0,225 <-0,225 =>ncuci2 =0,075 +0,225 = 0,3mol v a y V = ^ = 0,60(1) Dap an dung la C.