题干

下列溶液一定是碱性的是(  )


A:pH>7的某电解质的溶液   

B:c(OH﹣)>1×10﹣7mol/L

C:溶液中含有OH﹣   

D:溶液中c(OH﹣)>c(H+)

上一题 下一题 0.0难度 选择题 更新时间:2019-09-07 04:44:43

答案(点此获取答案解析)

D

同类题4

阅读理解

    For Zack, the shave was more than just a way to fund lifesaving research. It was a way to honor his late brother, Taylor Frink.

    Taylor, a volunteer firefighter in North Carolina, was killed in a car accident last September. Before his passing, Taylor was an eager supporter of St. Baldrick's. He went bald(秃头)for the cause in 2015, supporting kids with cancer and raising money to find cures.

    As a local hero, Taylor was beloved by the community. When he died, more than 1, 000 people attended his funeral to pay their respects. Zack looked up to his brother and this was the reason why he decided to become a junior firefighter himself. They did everything together. Zack remembers.

    Zack knew his brother had planned to shave again in 2016, so without hesitation he decided to fill his shoes and registered to shave at the local St. Baldrick's event in Kinston, N. C.

    “He was always goodhearted, and I want to make my brother proud,” shares Zack.

    As part of Zack's kindnesses, he raised more than $ 1,000 for the St. Baldrick's Foundation primarily by selling T-shirts he designed. Leading up to the event, Zack also visited his city council, commissioner's office and challenged the local official department to get involved.

    “We are not going to let Taylor's name be forgotten. That is what I love about St Baldrick's,” says Jean Culbreth, volunteer event organizer. “Zack gets it. He gets that what he is doing is keeping his brother's name alive.”

    The day finally came and Zack took his seat under the clippers (剪具), not only to honor his brother but to help kids with cancer. It was a special moment for all, and by the end of the day the event had raised more than $ 22,000!

同类题5

阅读下面文段,完成后面问题。

给母亲念“防骗经”

      乡下母亲进城为我带小孩,萘余饭后给母亲念“防骗经”就成为我和妻子的头等失事。

     “碰到陌生人敲门,你莫开,强盗进来可不得了。”我告诉母亲。“遇到外人要抱小孩,莫搭理,硅到人贩子就坏了。”妻子附和着。“街头有人问路,记住就说不知道,有八九此人是个骗子。”我提醒母隶。“别人给你饮料喝,千万别动口,说不准里头就放有‘蒙汗药’。”娄子正告母亲。“即使地上掉了一包钱,你也剐捡,没准那就是一个天大陷阱。”我以报上真事向母亲佐证。“有人低价倒卖元宝,你别动心,那元宝是纸糊的。”妻拿周围同事亲身经历向母亲诉说……每当这些“惊心动魄”的“传奇故事”从我们嘴里进出,母亲总瞪大了眼,说会这样吗?不会这样吧。我就不厌其烦地开导地:“这是城市,是大城市,哪能与乡村比!复杂呢。”母亲就似懂非懂地点着头。

      就这样平安无事了好几个月。一天,我下班归来,见母亲衣上有点点血迹,吃了一惊,赶紧瞧瞧睡在床上的儿子,儿子安然无恙,就问母亲出了啥事?母亲吞吞吐吐,说没事。妻说别瞒着,免得让我们担心。母亲这才说今天早上出门买菜。远远就见一个人骑摩托车撞在电线杆上,人摔得老远,大家固着却都不动,伤者头部己汩汩流血,母亲走了几步,又不放心折了回来,扶起那人,并对其伤口进行了简单包扎,这时警察驾车也赶到了,就一齐送到了附近的医院“哎哟,说了多少遍,谁叫你多事!?”娄子就嚷起来,“你不知道报上常登这些忘恩负义之徒反而说是你撞上他的,要你掏医药费。”

      “周围没人认识你吧”,我也不安起来,“这两天就少出门,免得让人认出带来不必要的麻烦。”我安慰母亲。

      母亲像做了错事的孩子,坐在椅子上,不敢正眼看我们。晚餐后,就听见屋外有人敲门,我的心一沉,和妻对望了一下,犹豫不决,敲门声更急促了,我只得起身。

      门外立着一个黑大个,满脸络腮胡须,粗声粗气问我:“你家是不是住着一个老太大?”

      我的心缩紧了,忙说:“你有什么事?”

      黑大个却不管三七二十一,径直闯进了屋里,就一眼望见了角落里的母亲,跑过去拉住母亲的手,说:“是你送我父亲上的医院吧,你让我找得好苦呀!”

      “你想干啥?”母亲挣扎着抽手出来,惊惶地看着黑大个。

      “你到底有什么事?”我拉开了汉子,“我娘可是好心呀,你可别冤枉好人。”

      “哎呀,老兄哪里话,你误会了。”汉子摇摇头,“我哪敢冤枉老妈妈,我是特意来谢谢你母亲的,没有你母亲,我爹说不定会出多大事呢。”

      汉子告诉我,清醒过来的老父第一件事就是命他去找那好心的老妈妈,说受人之恩当涌泉相报,他找了一个下午,问遍了菜场的人,才打听到老妈妈住在这里。

      汉子千恩万谢地走了,我们俩面面相觑,妻子望了母亲一眼,不好意思地上厨房洗碗去了,我再看看母亲,母亲仍在忙活手上的针线,还是不敢抬头看我们。