欲配制pH为5左右的缓冲溶液，应选择下列哪种共轭酸碱对( )。
A: HSO[img=11x26]1803dd4b1050089.png[/img]-SO[img=17x27]1803dd4b1955ef2.png[/img]([img=27x26]1803dd4b2265f15.png[/img]=1.2×[img=35x22]1803dd4b2c0e096.png[/img])
B: HCOOH-HCOO[img=11x21]1803dd4b34ed520.png[/img]([img=27x26]1803dd4b3ef6733.png[/img]=1.71×[img=35x22]1803dd4b4785c08.png[/img])
C: HAc-Ac[img=11x21]1803dd4b4f6ad95.png[/img]([img=27x26]1803dd4b5803f26.png[/img]=1.754×[img=35x22]1803dd4b611c8f3.png[/img])
D: NH[img=11x26]1803dd4b6a22e3d.png[/img]-NH[img=7x22]1803dd4b7352db8.png[/img]([img=27x27]1803dd4b7cbc50c.png[/img]=1.78×[img=35x22]1803dd4b859fe5f.png[/img])
A: HSO[img=11x26]1803dd4b1050089.png[/img]-SO[img=17x27]1803dd4b1955ef2.png[/img]([img=27x26]1803dd4b2265f15.png[/img]=1.2×[img=35x22]1803dd4b2c0e096.png[/img])
B: HCOOH-HCOO[img=11x21]1803dd4b34ed520.png[/img]([img=27x26]1803dd4b3ef6733.png[/img]=1.71×[img=35x22]1803dd4b4785c08.png[/img])
C: HAc-Ac[img=11x21]1803dd4b4f6ad95.png[/img]([img=27x26]1803dd4b5803f26.png[/img]=1.754×[img=35x22]1803dd4b611c8f3.png[/img])
D: NH[img=11x26]1803dd4b6a22e3d.png[/img]-NH[img=7x22]1803dd4b7352db8.png[/img]([img=27x27]1803dd4b7cbc50c.png[/img]=1.78×[img=35x22]1803dd4b859fe5f.png[/img])
举一反三
- 欲配制pH为5左右的缓冲溶液，应选择下列哪种共轭酸碱对( )。 未知类型：{'options': ['HSO[img=11x26]17de8811565c714.png[/img]-SO[img=17x27]17de881161bd3bc.png[/img]([img=27x26]17de88116d82326.png[/img]=1.2×[img=35x22]17de88117a82754.png[/img])', 'HCOOH-HCOO[img=11x21]17de8811865d4d4.png[/img]([img=27x26]17de88119fe803c.png[/img]=1.71×[img=35x22]17de8811ab9313a.png[/img])', 'HAc-Ac[img=11x21]17de8811b86c99b.png[/img]([img=27x26]17de8811c3f9550.png[/img]=1.754×[img=35x22]17de8811cfb8375.png[/img])', 'NH[img=11x26]17de8811dbfe7e4.png[/img]-NH[img=7x22]17de8811e938480.png[/img] ([img=27x27]17de8811f75adc7.png[/img]=1.78×[img=35x22]17de881202af432.png[/img])'], 'type': 102}
- 设[img=127x53]17f1b3d6db98b83.jpg[/img]，f（x）=arctanΧ，则[img=56x55]17f1b3d82842941.jpg[/img]=（）。 A: π B: 3π/4 C: -3π/4 D: 2π
- 已知随机变量X的分布函数为[img=136x49]1803b69024c8270.png[/img] ，则X的均值和方差分别为 A: E(X)=2, D(X)=4 B: E(X)=4, D(x)=2 C: [img=162x43]1803b6902cd8bfb.png[/img] D: [img=162x43]1803b69034d9ffd.png[/img]
- 设随机变量X的概率密度为[img=172x58]1802fe3273041d3.png[/img]则使得F{X > a} = F{X < a}成立，则a为( ). A: 2-1/4 B: 21/4 C: 1/2 D: 1-2-1/4
- 求不定积分[img=121x54]17da653839aa6ae.png[/img]； （ ） A: log(x^2 + 3*x + 25/4)/4 + (5*atan(x/2 + 3/4))/4 B: log(x^2 + 3*x + 25/4)/4 C: (5*atan(x/2 + 3/4))/4 D: log(x^2 + 3*x + 25/4)/4 - (5*atan(x/2 + 3/4))/4