EASY
Earn 100

The emperical formula of compound is CH2O . If its molecular weight is 180. The molecular formula of the compound is

50% studentsanswered this correctly

Important Questions on Some Basic Concepts of Chemistry

HARD
In Carius method of estimation of halogens, 250 mg of an organic compound gave 141 mg AgBr. What is the percentage of bromine in the compound (atomic mass of Ag=108 and atomic number of Br=80)?
EASY
An organic compound contains 80% (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is: [Atomic wt. of C is 12 and of H is 1]
MEDIUM

Compound A contains 8.7% Hydrogen, 74% Carbon and 17.3% Nitrogen. The molecular formula of the compound is, Given : Atomic masses of C,H and N are 12,1 and 14 amu respectively.

The molar mass of the compound A is 162 g mol-1.

EASY
An organic compound contains 24% carbon, 4% hydrogen and remaining chlorine. Its empirical formula is
EASY
The percentage of nitrogen by mass in ammonium sulphate is closest to (atomic masses H = 1, N = 14, O = 16, S = 32)
MEDIUM
An organic compound contains 60%C; 4.48%H and 35.5% O. Its empirical formula is
EASY
The percentage composition of carbon by mole in methane is:
MEDIUM
The empirical formula and molecular mass of a compound are CH2O and 180 g respectively. The molecular formula of the compound will be
MEDIUM
In a compound C, H and N are present in 9:1:3.5 by weight. If molecular weight of compound is 108, the molecular formula of compound is
HARD
A 1.85 g sample of an arsenic-containing pesticide was chemically converted to AsO43-  (atomic mass of As = 74.9) and titrated with Pb2+ to form Pb3 AsO42 . If 20 mL of 0.1 M Pb2+ is required to reach the equivalence point, the mass percentages of arsenic in the pesticide sample is closest to
EASY
1.25 g of a metal (M) reacts with oxygen completely to produce 1.68 g of metal oxide. The empirical formula of the metal oxide is [Molar mass of M and O are 69.7 g mol-1 and 16.0 g mol-1 , respectively]
HARD
One mole of one of the sodium salts listed below, having carbon content close to 14.3% produces 1mole of carbon dioxide upon heating (Atomic masses: Na = 23, H = 1, C = 12, O = 16). The salt is
MEDIUM
A sample of a hydrate of barium chloride weighing 61 g was heated until all the water of hydration is removed. The dried sample weighed 52 g. The formula of the hydrated salt is: (atomic mass, Ba = 137 amu, Cl = 35.5 amu)
HARD
An organic compound contains C, H and S. The minimum molecular weight of the compound containing 8% Sulphur is
EASY
In an estimation of bromine by Carius method, 1.6g of an organic compound gave 1.88g of AgBr. The mass percentage of bromine in the compound is ..
(Atomic mass, Ag=108, Br=80 gmol-1
MEDIUM
Complex A has a composition of H12O6Cl3Cr. If the complex on treatment with conc. H2SO4 loses 13.5% of its original mass, the correct molecular formulas of A is:
[Given : atomic mass of Cr=52 amu and Cl=35 amu]
EASY
A pure compound contains 2.4 g of C,1.2×1023 atoms of H,0.2 moles of oxygen atoms. Its empirical formula is
HARD
The ratio of mass percent of C and H of an organic compound CXHYOZ is 6 : 1. If one molecule of the above compound CXHYOZ contains half as much oxygen as required to burn one molecule of compound CXHY completely to CO2 and H2O. The empirical formula of the compound CXHYOZ is
EASY
A compound has the following composition by weight; Na=18.60%, S=25.80%, H=4.02% and O=51.58% Assuming that all the hydrogen atoms in the compound are part of water of crystallization, the correct molecular formula of the compound is