Yahoo奇摩 網頁搜尋

1. phenolphthalein 的顏色： pink (or red) in alkali, colourless in alkali, pale pink (or very pale pink ) during...加入的 alkali 便是過多了。因此，很多時考試未必會接納 colourless to pink 這個答案。 是否接納 colourless to red 這個答案，我的答案是「何必...

...aq) The OH-(aq) formed will change the phenolphthalein indicator to pink .

...2. Water vapour turns dry cobalt chloride paper from blue to pink . 1.二氧化碳會將石灰水轉成乳白色 2.水蒸氣會將乾的氯化鈷試紙由藍色轉成粉紅色...

I think you may be in form 2 In f2 level, only hexahydrate cobalt(II) chloride paper(contain hexahydrate cobalt(II) chloride solution) will turn from pink to blue by dehydrating it The use of hair dryer is dehydrating.

Indicator solution : Phenolphthalein pink in alkali solution, the pink colour will turn to colourless when the ammonia is neutralized or evaporated

... several e.g. Fe3+ green Fe2+ brown/yellow Mn2+ pale pink Ni2+ green Cr3+ green Co2+ pink Mn2O32- purple...

...gt; 5Fe3+ + Mn2+ + 4H2O 　 Fe2+ : green MnO4 - : pink to purple 　 若有 Fe2+ 存在，則溶液為淺綠色，MnO4 - 加入，立即...

phenolphthalein is pink when pH>8, since NaCl is neutral, pH=7, vinegar is acidic, pH<7, phenolphthalein is colourless at thses pH range. 用pH paper 就可以了