首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Chlorine is a mainstay in most swimming pools in the United States, and is used to eradicate bacteria. A bacteria-free pool will
Chlorine is a mainstay in most swimming pools in the United States, and is used to eradicate bacteria. A bacteria-free pool will
admin
2017-05-11
43
问题
Chlorine is a mainstay in most swimming pools in the United States, and is used to eradicate bacteria. A bacteria-free pool will usually ensure that swimmers won’t contract a serious illness if they spend time in, and possibly ingest, the water. When chlorine is added to pool water, a chemical reaction occurs whereby the chlorine breaks down into a legion of chemicals that combine to kill bacteria that may be in water. These chemicals, specifically hypochlorous acid and hypochlorite ion, eliminate bacteria by annihilating and then oxidizing the abhorrent cells. When this chemical reaction occurs, the baeteria are rendered essentially harmless. This chemical reaction doesn’t occur immediately — individual components within chlorine take varying amounts of time to interact with the bacteria, creating an almost time-release-type of kill in the pool water.
Chlorine must be regularly replenished. As they react, the hypochlorous acid and hypochlorite ion combine to create a particular acceptable pH level in the pool water. A pH is a measure of the alkalinity and acidity present; a pH value of 7 represents a neutral value, and 7. 4 is the pH value of the human tear. The pH ratio must be regularly monitored to ensure a consistent optimum ram — one usually kept within the spectrum of 7 to 8 as measured by a reliable pH measuring kit. As the chemicals in chlorine complete their reactions, they break down and are no longer effective in keeping the pool water neutralized. Additional chlorine must be added to water at specific times. Outdoor pools that are in direct sunlight need to have water added more often because the chemical reaction time for chlorine is increased and its effectiveness is reduced in these conditions. Since the hypochlorite ion is an especially potent chemical capable of fading fabrics and paint, most people are meticulous about rinsing chlorine from potentially affected areas. Although chlorine is inexpensive and widely available, some people find the bleach smell to be repugnant and the distinct aroma present at many swimming pools to be overwhelming. These people may not be able to enjoy aquatic pursuits in those pools that employ chlorine as a cleansing agent. Other people may find that inhaling chlorine at the high levels present around some pools may be difficult to tolerate. Still others may experience skin irritation after swimming in a pool containing chlorine. Although there are other chemicals and compounds available to clean swimming pools, they may be prohibitively expensive or incapable of killing all types of bacteria present in the water.
According to the passage, a stable pH value in pool water is dependent upon which of the following?
选项
A、Monitoring and adding chlorine when warranted.
B、Ensuring that there is only a minimum amount of bacteria in the water.
C、Paying close attention to the reactions of chemicals in the pool water.
D、Ensuring that water is protected from direct sunlight.
答案
A
解析
细节题。从第二段第一句话“Chlorine must be regularly replenished“以及”TheoH ratio must be regularly monitored to ensure a consistent optimum…”可知正确答案是A。
转载请注明原文地址:https://kaotiyun.com/show/oRFO777K
0
考博英语
相关试题推荐
Itthispart,youareexpectedtowriteacompositionentitledPressuresofModemManinnolessthan200words.Yourcompositio
Peoplethatlivingintheworldforthesamelongtimemayexperiencedifferentwaysoflife:somepeoplewalkfarandcanenjoy
Forseveralyears,scientistshavebeentestingasubstancecalledinterferon(干扰素),apotentialwonderdrugthatisprovingtobe
Increasingnumbersofpeoplehavemigratedfromthecountrysideandmovedintotownsandcitesover【R1】______.Mostareintile
Hurricanesareviolentstormsthatcausemillionsofdollarsinpropertydamageandtakemanylives.Theycanbeextremelydange
Itdidn’thappenovernight.Theproblemofpollutedairhasbeenfesteringforcenturies.Suddenlytheproblemofairpollut
InJuly,almostunnoticedbythenationalpress,adeadlybirdvirusarrivedonapheasantfarminSurrey.ExpertsfromtheDepa
Famehappenedalmostovernightforthe25-year-oldactress,butshehasbecome_____byalltherecentmediaattentionandnowshe
Ifthenationalpastimecouldbeintegrated,itseemedonlyamatteroftimebeforethenation’sschools,playgrounds,buses,andre
Thisdecreasesthedevicethicknessanddepletionvoltageand______reducesmaterialqualityrequirementsandcostofthedetec
随机试题
在通货膨胀情况下,由于投机利益的驱动,商品会长期滞留在()。
教师申诉制度
A、出现突发性聋B、氮质血症C、耐药菌株迅速出现,变态反应发生率提高D、肾性尿崩症E、厌食、激动、皮肤瘙痒等两性霉素B因引起远曲小管坏死而致
小儿久泻不止,其主要病理是
多用于分期导流后期阶段的导流方式是()。
下列内容中,构成自营基建项目工程成本的有()。
金融期权的基本功能包括()。Ⅰ.套期保值Ⅱ.投机Ⅲ.套利Ⅳ.价格转移
下列评价方法中,可用于寿命期不同的互斥方案选择的有()。
为了研究和预报空间天气灾变规律,______或减轻灾害性空间天气可能给人类活动带来的灾害和损失,一门把空间天气的监测、研究、模式、预报、效应、信息传输与处理以及对人类活动的影响加以综合形成的新学科______。
NewProductWillSaveLivesDrinkingwaterthatlookscleanmaystillcontainbugs(虫子),whichcancauseillness.Asmallcom
最新回复
(
0
)