10th Class Science Metals and Non-metals Question Bank 10th CBSE Science Metals and Non-metals

  • question_answer   Shashi bought new silver anklets. After a month she found that the anklets turns black. She has doubt that it is not of pure silver but her neighbour Rakhi advised her that it is of pure silver and wash it with tamarind or lemon juice to get the luster back. She followed the advise and get the lustre of her anklet back.          Answer the following questions based on the above passage. (a) Do you think that the anklets are not of pure silver? (b) Why these turn black after sometime? (c) Why the anklets become lustrous on washing with tamarind or lemon juice? (d) What values are exhibited by Rakhi?

    Answer:

                      (a) No, these are pure.                                     (1) (b) Anklets turned black due to the reaction of silver with atmospheric  which results in the formation of black coloured silver sulphide.                                                             (1) (c)  dissolves in acids present in tamarind or lemon juice, so the anklets got their lustre back.                                               (1) (d) The values exhibited by Rakhi are (i) Awareness (ii) Helpful (iii) Knowledgeable. (2)


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