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  1. Metanoia

    Chemistry: Post your doubts here!

    i) moles of OH- in filtrate = moles of HCl used in neutralization = 0.2 x 0.018 = 0.0036 mol ii) moles of OH- from KOH = 0.1 x 0.025 = 0.0025 mol moles of OH- from M(OH)3 = 0.0036 - 0.0025 = 0.0011 mol [OH-] from M(OH)3 = 0.0011/0.025 =0.044 mol/dm^3 iii) M(OH)3 <--> M3+ + 3OH- [M3+] = 0.044/3...
  2. Metanoia

    Chemistry: Post your doubts here!

    Ka= (H+)(salt) / (acid ) log Ka = log [(H+)(salt) / (acid )] log Ka = log (H+) + log [(salt)/(acid )] -log (H) = - log Ka + log [(salt)/(acid )] pH = pKa+ log [(salt)/(acid )] pH = 7.2 + log (0.002/0.005)
  3. Metanoia

    Chemistry: Post your doubts here!

    Dibasic acid means it releases 2 moles of H+ per mole of acid. So ratio of dibasic acid : NaOH is 1: 2
  4. Metanoia

    Chemistry: Post your doubts here!

    Yes. What you've written is fine.
  5. Metanoia

    Chemistry: Post your doubts here!

    You are using a half equation where the concentrated sulfuric acid acts as an oxidizing agent. That does not happen with chlorides (i.e. LiCl).
  6. Metanoia

    Chemistry: Post your doubts here!

    To be fair, its not an irrelevant question. Rather, its a question that requires deeper understanding of the concepts covered at A levels.
  7. Metanoia

    Chemistry: Post your doubts here!

    My suspicions are your friend might be thinking of instantaneous dipoles-induced dipoles; but will see wait and see what the confusion might be.
  8. Metanoia

    Chemistry: Post your doubts here!

    Don't really make sense to me. Van der waals are the attraction of electron clouds to nucleus of neighboring molecules, what does it have to do with distribution?
  9. Metanoia

    Chemistry: Post your doubts here!

    Fe2(SO4)3 (aq) --> 2 Fe3+ + 3 SO42-
  10. Metanoia

    Chemistry: Post your doubts here!

    Density of the gases is related to the Mr of the gases in the mixture and their % composition. For example, for option A = 0.898 x 2 + 0.102 x 4 = 2.204 Repeat for the other options and choose the highest value among the 4 options.
  11. Metanoia

    Chemistry: Post your doubts here!

    Oxidation state of Cr in Cr2O7 2- is +6 (not +12), we look at individual Cr, not the total of all Cr. The "VI" in the name dichromate (VI) should already give us the idea that its oxidation state is +6.
  12. Metanoia

    Chemistry: Post your doubts here!

    Qn 4. Qn 15. Most likely you've overlooked the info that only 25 cm3 out of the 250 cm3 was used for titration. Qn 28. Qn 31. You have to write out the configuration of V atom first and then remove electrons from the outer shells. Qn 37. I have actually explained a similar question (qn...
  13. Metanoia

    Chemistry: Post your doubts here!

    Qn 30. A bit hard for me to see your picture. I've attached my solution for you to compare. Qn 39. The green color is due to the Cr3+ ions, not the organic products. Qn 40. CN- is a negative ion and is thus a stronger nucleophile than the neutral HCN.
  14. Metanoia

    Chemistry: Post your doubts here!

    That is not the correct half equation to use. The equation should be a redox equation. Fe2+ --> Fe3+ + e- Adding the Na+ and SO42- ions to the solution does not affect the equilibrium. I have relooked at the question and spotted my mistake. The concentration of Fe2(SO4)3 is o.1 mol/dm3...
  15. Metanoia

    Chemistry: Post your doubts here!

    No short cut. At the most, you can focus on the tertiary isomers first to narrow down the options to 2 choices. Then move on to the secondary isomers.
  16. Metanoia

    Chemistry: Post your doubts here!

    It could be ethanal or ethanoic acid, depending on the conditions. The question is asking for an organic product that is colored, and neither ethanal or ethanoic acid is colored. The green color is due to the Cr3+ ions.
  17. Metanoia

    Chemistry: Post your doubts here!

    Qn 6. Original Mr (CaCl2) = 111 Final Mr (CaCl2.2H2O) = 147 % Increased in Mr =(36/111) x 100% = 32% Qn8. Moles of Cr2O7 2- = 0.00131 mol Moles of Fe2+ = 0.00131 x 6 = 0.00786 mol Mass of Fe = 0.00786 x 56 = 0.44 g % of Fe = (0.44/1) x 100% = 44% Qn17. Describing an element that forms an...
  18. Metanoia

    Chemistry: Post your doubts here!

    In acidic solutions, balance the equations in order of AOHE (atoms, oxygen, hydrogen and electrons). Balance the atoms apart from oxygen and hydrogen. Balance the oxygens by adding water molecules. Balance the hydrogens by adding hydrogen ions. Balance the charges by adding electrons. For...
  19. Metanoia

    Chemistry: Post your doubts here!

    Yes, that's right. Conservation of mass.
  20. Metanoia

    Chemistry: Post your doubts here!

    Collect the water through condensation. As for the nitrogen oxide, a gas syringe should suffice.
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