CIE Chemistry Paper-1: Specimen Questions 54 - 55 of 99
Question number: 54
Which of the following fruit contains citric acid?
Oranges and Mangoes
Lemons and Mangoes
Lemons and Oranges
Lemons and blueberries
Citric acid is most prevalent in citrus fruits and juices. Of these fruits, lemons and limes have the most citric acid. While oranges, grapefruits, and berries also contain appreciable amounts, lemons and limes will most significantly contribute to the citric acid content of your urine.
Question number: 55
Which of the following statements are incorrect for alkali metals?
i) They are good reducing agent.
ii) They impart colour to the flame.
iii) They are found in nature in combined state.
i) and ii)
|d.||None of the above|
- The alkali metals have low value of ionization energy which decreases down the group and so can easily lose their valence electron and thus act as good reducing agents.
- When burning, the alkali metal they get very excited, promoting their outmost electrons to higher energy levels. Eventually, upon cooling, the elements will have their electrons coma back to a lower energy level. The difference in energy is emitted in the form of a photon. That energy correspond to a specific wavelength.
- Alkali metals are all too reactive to remain in their isolated, uncombined state. They spontaneously react with oxygen, water, and any number of other things that are ever present in the ambient surroundings. Therefore, they are only found as compounds in nature.