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  1. histephenson007

    Chemistry MCQ thread...

    Which one is it C or A?? plz explain
  2. histephenson007

    Chemistry MCQ thread...

    Q. When a mineral was heated in a Bunsen flame to constant mass, a colourless gas that turned limewater mily was evolved. The remaining solid was cooled and then added to aqueous hydrochloric acid. Vigorous effervescence was seen. What was the mineral? A. aragonite, CaCO3 B. artinite...
  3. histephenson007

    Chemistry MCQ thread...

    I don't think any calculations are involved in this question., First of all, we know that it doesn't react with MnO4/H+ (which is an oxidant)...which shows that the alcohol is tertiary. so we get the basic layout..... (CH3)3 C-OH But, the molecule has to have a chiral centre... so we just...
  4. histephenson007

    Chemistry MCQ thread...

    yea I guess its correct plz continue with ur explanation...
  5. histephenson007

    Chemistry MCQ thread...

    For 26, is C right???
  6. histephenson007

    Chemistry MCQ thread...

    ah... I forgot that they are shown as empirical formula ... So, B IS a nitrate, but C isn't because nitrate is NO3 and C has only one atom of oxygen.
  7. histephenson007

    Chemistry MCQ thread...

    Answer is D. Facts : - liberated gas is NH3 (turns damp litmus paper blue) - options B and C are eliminated because they aren't nitrates!! (question mentions that it is a solid nitrate) - ammonium salts react with alkalis to produce ammonium gas ( a new knowledge I've learned from this very...
  8. histephenson007

    Chemistry MCQ thread...

    Is the answer for 3... A?
  9. histephenson007

    Chemistry MCQ thread...

    But one thing I notice about this question is that the enthalpy change of formation of carbon monoxide in the product of the equation isn't considered?? could u plz explain why?
  10. histephenson007

    Chemistry MCQ thread...

    m=0.23 V= 120 cm^3 =====> 120/1000 dm^3 n = V/24 (gas) = (120/1000) / 24 = 0.005 Therefore, we can get Mr.. Mr = m/n = 0.23/0.005 = 46 Then, u just try putting in each values of N(14) and O (16) Answer : B
  11. histephenson007

    Chemistry MCQ thread...

    Is the answer C ?? I hope I could draw to show my explanation... CO2+H2---->CO+H20(g) *** notice the H2O (g) If we draw a different pathway for the reaction... C+H2+O2---(-283)--> CO2+H2-----(x)--->CO+H2O(g)-----(-44)--->CO+H20(l) <----(-286) H2+O2 So, -283+x-44=-286 therefore x =...
  12. histephenson007

    Chemistry MCQ thread...

    Which question r u talking about?? The one from section b?? then, its wrong
  13. histephenson007

    Chemistry MCQ thread...

    Another question... this time I have another question.. When finding chiral centres in cycloalkanes...how do u differentiate if there is a chrical centre or not... In this case, how should I know that A doesn't have a chiral centre and D does??
  14. histephenson007

    Chemistry MCQ thread...

    Could any1 plz explain this question? plzz...
  15. histephenson007

    Chemistry MCQ thread...

    Right, right...sorry my bad
  16. histephenson007

    Universities in India?

    Can anyone suggest a few good ones for medicine in India??
  17. histephenson007

    Chemistry MCQ thread...

    But D is a carboxylic acid too! wouldn't the answer be A??
  18. histephenson007

    Chemistry MCQ thread...

    The question asked u to find how many atoms of silver were deposited per cm2, so you're answer was incomplete
  19. histephenson007

    Chemistry MCQ thread...

    Mass of Ag = 0.216 g n of Ag = 0.216/108 = 0.002 number of atoms of Ag = 0.002 * Avogardo's constant = 0.002*(6.02*10^23) = 1.204 * 10^21 Finally, number of atoms per cm2 = (1.204*10^21) / 150 = 8.0*10^18 Therefore, answer = A
  20. histephenson007

    Chemistry MCQ thread...

    Actually, that was the same thing I was unsure about. But, I thought, if it is in O2 state, another bond needs to be broken for the reaction to occur. So, Activation energy isn't completely achieved. Correct me if I'm wrong/
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