Attention Chemistry experts please.

[Rohaan]

The 5th,16th and 21st M.C.Qs of 2003 may june are somewhat tricky and difficult.I need help.

 

[Aiqbal]

The 5th,16th and 21st M.C.Qs of 2003 may june are somewhat tricky and difficult.I need help.

O or A

 

[Rohaan]

O-level

 

[A star]

The 5th,16th and 21st M.C.Qs of 2003 may june are somewhat tricky and difficult.I need help.

link? and post it in the chemistry or create new thread in O level section more queries will bw answered at twice the speed

 

[sweetiepie]

https://www.xtremepapers.com/community/threads/biology-chemistry-physics-post-your-doubts-here.9672/ post here your doubts

 

[drakken1997]

5. D. Because H2SO4, being a dibasic acid, contributes two moles of H+ ions for each mole of it that dissolves in water. So, 0.025 moles give 0.05 moles of H+. Then calculate the conc. using the formula.
16. C. This is a question on Le Chateliers Principle. If more oxygen is supplied, then the equilibrium will adjust to go to the reaction which produces less oxygen. Thus, more NO2 will be produced, and so the colour becomes darker brown.
21. C. C is a precipitation reaction. The others are typical acid reactions i.e. metal hydroxide + acid= salt + water. Metal oxide + acid= salt + water. And metal carbonate+acid= salt+CO2 + H2O

 

[Rohaan]

Thanks bud.