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Niranjan Barla’s Chemistry Questions


On 19th Feb, 2010, Niranjan Barla sent these questions:

Can u plz answer this ques??

1. The wooden shelves on which conc.Sulphuric Acid bottles are kept are
stained black. Why?
2. Dot diag. of ethyne.

Our Answers:

1. Sulfuric-acid

Conc. Sulphuric acid has a very strong affinity for water, which is the reason behind its dehydrating property. It reacts with wood (which is a type of cellulose) to dehydrate it (remove the molecules of water from the wood), leaving behind a layer of carbon, which causes the black stain on the wooden shelves on which it is kept.

[C6H5O10]n ———- 6[C]n + 5[H2O]n

2. ethyne

Dot diagram of ethyne

H:C:::C:H

or

H-C—C-H

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7 Responses to “Niranjan Barla’s Chemistry Questions”

  1. S.MAJUMDER says:

    Iron and sodium are elements but sodium sulphate is a compound pl explain.

  2. Aayushi says:

    why the size of electrodes get reduced when the anode of copper is taken,
    with the electoryte being CuSO4.
    plz give full description

  3. sayali says:

    wat should b the nature of anode in eletroplating an article with silver

  4. swapnika says:

    @ Aayushi:
    Copper,nickel and silver are active electrodes which means that they take part in the electrolytic reaction discharging into their respective ions. when current is passed through the electrolyte the concentration of the ions decreases which are replaced by the ions from the anode. Therefore the size of electrode decreases.

  5. swapnika says:

    @ sayali
    the electrode should be active inorder to electroplate the requried metal on the article.

  6. swapnika says:

    why is conc. sulphuric acid weaker acid compared to dil.sulphuric acid?

  7. Ishan says:

    Give a reason why conc. and not dil. H2SO4 behaves as an oxidizing and a dehydrating agent ?

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