• 2022-07-24
    两性生物碱在水溶液中沉淀的pH值为
    A: 1
    B: 10
    C: 6~7
    D: 2~3
    E: 8~9
  • E

    举一反三

    内容

    • 0

      动植物在水中能生存的pH值范围为()。 A: 7~8 B: 6~9 C: 3~7 D: 2~8

    • 1

      将等体积pH=3的HCl溶液和pH=10的NaOH溶液混合后,溶液的pH区间是() A: 1~2 B: 3~4 C: 6~7 D: 8~9 E: 11~12

    • 2

      下列数组声明语句中正确的是( )。 A: Dim A(9) As Single = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 } B: Dim A( ) As Single = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 } C: Dim A( ) As Single = { 1, "abc", "ccc", 4, 5, 6, 7, 8, 9, 10 } D: Dim A( , ) As Single = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }

    • 3

      >>>x= [10, 6, 0, 1, 7, 4, 3, 2, 8, 5, 9]>>>print(x.sort()) 语句运行结果正确的是( )。 A: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10] B: [10, 6, 0, 1, 7, 4, 3, 2, 8, 5, 9] C: [10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0] D: ['2', '4', '0', '6', '10', '7', '8', '3', '9', '1', '5']

    • 4

      下列数组声明语句中,不正确的是_________。 A: Dim a(9) As Single = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10} B: Dim a() = {1, 2, 3, 4, 5, 6, 10} C: Dim a( ,) As Single = {{1, 2, 3, 4, 5}, {6, 7, 8, 9, 10}} D: Dim a() As Single = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10} E: Dim n As Integer=10Dim a(n) As Single