19,000+ solved questions for JEE Advanced, JEE Mains, NEET & IChO — with answers and expert explanations.
20.0 g of a magnesium carbonate sample decomposes on heating to give carbon dioxide and 8.0g magnesium oxide. What will be the percentage purity of magnesium carbonate in the sample ? (NEET 2015)
If Avogadro number NA, is changed from 6.022 × 1023 mol–1 to 6.022 × 1020 mol–1, this would change (NEET 2015)
The number of water molecules is maximum in (NEET 2015)
What is the mass of the precipitate formed when 50 mL of 16.9% solution of AgNO3 is mixed with 50 mL of 5.8% NaCl solution? (Ag = 107.8, N = 14, O = 16, Na = 23, Cl = 35.5) (NEET 2015)
Suppose elements X and Y combine to form two compounds XY2 and X3Y2. When 0.1 mol of XY2 weighs 10g and 0.05 mol of X3Y2 weighs 9g, the atomic weights of X and Y are (NEET 2016)
Which of the following is dependent on temperature? (NEET 2017)
In which case is number of molecules of water maximum? (NEET 2018)
The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber’s process is (NEET 2019)
The density of 2 M aqueous solution of NaOH is 1.28 g/cm3. The molality of the solution is [Given that molecular mass of NaOH = 40 g mol–1] (Odisha NEET 2019)
Which one of the following has maximum number of atoms? (NEET 2020)
An organic compound contains 78% (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, H is 1] (NEET 2021)
What mass of 95% pure CaCO3 will be required to neutralise 50 mL of 0.5 M HCl solution according to the following reaction? CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + 2H2O(l) [Calculate upto second place of decimal po…
In one molal solution that contains 0.5 mole of a solute, there is (NEET 2022)
100 mL of mixture of NaOH and Na2SO4 is neutralised by 10 mL of 0.5 M H2SO4. Hence, NaOH in 100 mL solution is
P and Q are two elements which forms P2Q3 and PQ2. If 0.15 mole of P2Q3 weights 15.9g and 0.15 mole of PQ2 weights 9.3g, the atomic weight of P and Q is (respectively) :
If we consider that 1/6, in place of 1/12, mass of carbon atom is taken to be the relative atomic mass unit, the mass of one mole of a substance will
Number of atoms in 560g of Fe (atomic mass 56 g mol–1) is
The total number of electrons present in 18 ml of water (density of water is 1 g ml–1) is
A 27.0 g sample of an unknown hydrocarbon was burned in excess O2 to form 88g of CO2 and 27g of H2O. What is possible molecular formula of hydrocarbon ?
When a hydrate of Na2CO3 is heated until all the water is removed, it loses 54.3 per cent of its mass. The formula of the hydrate is
Assertion : Both 138 g of K2CO3 and 12 g of carbon have same number of carbon atoms. Reason : Both contains 1 g atom of carbon which contains 6.022 × 1023 carbon atoms.
Assertion :Both 12g of carbon and 27g of aluminium contain 6.023 × 1023 atoms. Reason :Molar mass of an element contains Avogadro number of atoms.
Assertion :Number of molecules present in SO2 is twice the number of molecules present in O2. Reason : Molecular mass of SO2 is double to that of O2.
Assertion : If 30 mL of H2 and 20 mL of O2 react to form water, 5 mL of H2 is left at the end of the reaction Reason :H2 is the limiting reagent.
Assertion :For a binary solution of two liquids, A and B, with the knowledge of density of solution, molarity can be converted into molality. Reason: Molarity is defined in terms of volume and molality …