18.下列物质一定互为同系物的是( )
| A. | C2H4和C3H4 | B. | C2H6和C4H10 | C. | CH2O2和C2H4O2 | D. | C2H2和C6H6 |
12.25℃在pH=0或pH=14的溶液中,都能大量共存的离子组是( )
0 170567 170575 170581 170585 170591 170593 170597 170603 170605 170611 170617 170621 170623 170627 170633 170635 170641 170645 170647 170651 170653 170657 170659 170661 170662 170663 170665 170666 170667 170669 170671 170675 170677 170681 170683 170687 170693 170695 170701 170705 170707 170711 170717 170723 170725 170731 170735 170737 170743 170747 170753 170761 203614
| A. | K+,I-,Cl-,SO42- | B. | Fe2+,Na+,Mg2+,Cl- | ||
| C. | SO32-,Na+,K+,NO3- | D. | NH4+,K+,AlO2-,NO3- |