A chalk sample exactly 17.52 gram HCl for complete reaction with all `CaCO_(3)` present in it. If the chalk sample is 72% pure, the mass of sample taken is
`CaCO_(3) + 2HCl to CaCl_(2) + H_(2)O+CO_(2)`
Moles of HCl `=(17.52)/(36.5)`
Moles of `CaCo_(3)=(1)/(2)xx(17.52)/(36.5)`
Weight of `CaCO_(3)` required `=(1)/(2)xx(17.52)/(36.5)xx100`
Mass of sample taken:
`=(1)/(2) xx(17.52)/(36.5)xx(100xx100)/(72)=33.33` gm
Correct Answer - B
`5As_2S_3+28KMnO_4+H^(+)to10H_3AsO_4+28Mn^(2+)+SO_4^(2-)`
meq of `As_2S_3`=meq. of `KMnO_4`
`X/246xx1000xx28=50xx0.1xx5 " " X=0.22 g`
`underset(100g)underset("1 mol")(CaCO_(3))+underset(73g)underset("2 mol")(2HCl(aq)) to CaCl_(2)(aq.)+H_(2)O(l)+underset(44g)underset("1 mol")(CO_(2)g)`
Let `CaCO_(3)(s)` be completely consumed in the reaction.
`therefore 100g CaCO_(3) "give" 44gCO_(2)`
`therefore 20g CaCO_(3)"will give" (44)/(100)xx20g CO_(2)=8.8CO_(2)`
Let HCl be completely consumed....
Correct Answer - C
The reaction is :
`underset(2xx122.5 kg)(2KClO_(3))(s) to 2KCl(s) + underset(3xx32 kg)(3O_(2)(g))`
Mass of `O_(2)` obtained by 10 kg `KClO_(3) = (96 xx 10)/(245) = 3.92 kg `]
Correct Answer - B
The reaction is :
`M_(2)CO_(3)+ 2HCl to 2Mcl + H_(2)O + CO_(2)`
Number of moles of `CO_(2)` = Number of moles of `M_(2)CO_(3)`
`0.01186 = ("Mass")/("Molar mass...
Correct Answer - A
`CaCO_(3)(s)rarrunderset(336kg)(CaO(s))+CO_(2)1g`
Moles of CaO = `(336)/(56)xx10^(3)=6xx10^(3)`
Mass of `CaCO_(3)` required `=6xx10^(3)xx(100)/(60)xx100=10^(3)kg`
Correct Answer - A::C
Given equation is `x^(2) + 2x sin(cos^(-1) y) + 1 =0`
Since x is real, `D ge 0`. Therefore,
`4(sin(cos^(-1)y))^(2) -4 ge 0`
or `(sin(cos^(-1)y))^(2) ge 1`...
Correct Answer - B
P (4 bases coin)`=1/3`
P(5 biased coin) `=1/4`
Hence, the required probability is
`=1/3(""^(4)C_(3)""^(16)C_(6))/(""^(20)C_(9))+2/3(""^(5)C_(4)""^(15)C_(5))/(""^(20)C_(9))(1)/(""^(11)C_(1))`
`=2/33[(""^(16)C_(6)+5""^(15)C_(5))/(""^(20)C_(9))]`