题目

室温下，某溶液中水电离出的H＋浓度为，则该溶液中一定不可能大量存在的离子是 A． Cl—            B．       C． Na＋            D． 答案：【答案】B 【解析】 试题分析：室温下，某溶液中水电离出的H＋浓度为，则可能是酸性溶液，也可能是碱性溶液，若为酸性溶液，则HCO3-会发生反应而不能大量存在，若是碱性溶液，则HCO3-会发生反应而不能大量存在，故选项是B。 考点：考查离子大量共存的知识。  Beauty has always been regarded as something praiseworthy. Almost everyone thinks attractive people are happier and healthier, have better marriages and have more respectable jobs. Personal advisors give them better advice for finding jobs. Even judges are softer on attractive defendants. But in the executive circle, beauty can become a liability.      While attractiveness is a positive factor for a man on his way up the executive ladder, it is harmful to a woman.      Handsome male executives were considered as having more honesty than plainer men; effort and ability were thought to lead to their success.      Attractive female executives were considered to have less honesty than unattractive ones; their success was connected not with ability but with factors such as luck.      All unattractive women executives were thought to have more honesty and to be more capable than the attractive female executives. Interestingly, though, the rise of the unattractive overnight successes was connected more to personal relationships and less to ability than that of the attractive overnight successes.      Why are attractive women not thought to be able? An attractive woman is considered to be more feminine and an attractive man more manly than the less attractive ones. Thus, an attractive woman has an advantage in traditionally' female jobs, but an attractive woman in a traditionally manly position appears to lack the "manly" qualities required.      This is true even in politics. "When the only clue is how he or she looks, people treat men and women differently," says Anne Bowman, who recently published a study on the effects of attractiveness on political candidates. She asked 125 undergraduate students to rank two groups of photographs, one of men and one of women, ir o_nler of attractiveness. The students were told the photographs were of candidates for political offices. They were asked to rank them again, in the order they would vote for them.      The results showed that attractive males completely defeated unattractive men, but the women who had ranked most attractive unchangeably received the fewest votes. 51. The word "liability" most probably means             A. disadvantage     B. advantage         C. misfortune        D. trouble 52. In traditionally female jobs, attractiveness              A. makes women look more honest and capable       B. strengthens the feminine qualifies required       C. is of no importance to women       D. often enables women to succeed quickly 53. Bowman's experiment shows that when it comes to polities, attractiveness               A. turns out to be a disadvantage to men       B. is more of a disadvantage than an advantage to women       C. affects men and women alike       D. has as little effect on men as on women 54. It can be inferred from the passage that people's views on beauty are often             A. practical     B. supportive      C. old-fashioned    D. one-sided 55. The author writes this passage to       A. give advice to job-seekers who are attractive       B. discuss the disadvantages of being attractive       C. demand equal rights for women       D. state the importance of appearance