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化学 高校生

Cがaとeだと思ったのですが、なぜeがだめなのか教えて欲しいです。bが正解なのは理解できてます!

ジを用いれば, 中和点 160 第2編 物質の変化 1142章 物質の変化 □□ 148 中和滴定曲線 次の図A~D は 0.10mol/L 図の酸(塩基) 10mL を同じ濃度の塩基(酸) で中和反応さ せたときの滴定曲線である。 図の縦軸はpH, 横軸は 加えた酸・塩基の滴下量を示している。 図Aは(ア) (イ)で,図B は (ウ) を(エ) で, 図Cは (オ) (カ) で, 図Dは(キ)を(ク)で滴定したもの である。 指示薬としては, メチルオレンジ (変色域: pH= 3.1~4.4) とフェノールフタレイン (変色域:pH = 8.0 ~ 9.8) を用いた。 (1) 文中の (ア)~(ク)に適する水溶液を (a)~(e) から選べ。 (a) 塩酸 (b) アンモニア水 (c) 硫酸 (d) 水酸化ナトリウム水溶液 (e) 酢酸水溶液 (2) 図A~Dの適定に適する指示薬をそれぞれ次の(a)~(d)から選べ。 (a) メチルオレンジのみが適している。 42086420 14 12 10 1412186420 0 10 P160 (b) フェノールフタレインのみが適している。 (c) メチルオレンジとフェノールフタレインの両方が適している。 (d) メチルオレンジとフェノールフタレインのどちらも不適である。 === 42086420 応用例題 31 NaOH と Na2CO の混合溶液の中和滴定 炭酸ナトリウムと水酸化ナトリウムの混合水溶液がある。この 薬としてフェノールフレ 14 12 10 20〔mL] 0 図A 10 14」 12 10 1020[mL] 0 図C 42086420 1020m 図 B 10 20ml 図 D 応用 159

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英語 高校生

(21)の答えが3になるのがなんでか少し分からないです…わかる方いますか??

(21) (22) (23) Any Change? Long ago, humans did not use money. Because they often could not produce everything that they needed, they traded some of their goods for goods made by others. Gradually, the goods that they exchanged were replaced by cash. For hundreds of years, metal coins and paper bills that can be exchanged for goods and services have been produced. Cash is convenient for many people because it is easy to carry. At the same time, though, it ( 21 ). Another disadvantage is that criminals have been able to produce fake coins and bills. In the middle of the 20th century, plastic credit cards were introduced. They had security features to prevent them from being used by anyone except their owners. At first, their use was limited to wealthy people. Over time, however, they became ( 22 ). In the last few years, apps for smartphones that can be used in the same way as credit cards have also become popular. Because of this, some people are suggesting that we may soon see the end of cash. Supporters of a "cashless" society in which all payments are made electronically argue that it would have several benefits. For example, people would not have to worry about keeping their wallets safe. However, some people are concerned that they might be unable to pay for the things they need because of a software error or a broken smartphone. Moreover, some people do not have bank accounts or credit cards, so their only option is to use coins and bills. ( 23 ), it seems as though societies will continue to use cash. 1 can be lost or stolen can be recycled 1 thinner and lighter 3 harder to use 1 For now 2 Until then 2 4 2 4 3 is used for shopping online is understood by almost everyone more colorful and exciting more widely available With luck 4 By contrast

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