Chemistry questions
29404 published questions with worked solutions.
- Number of molecules/ions from the following in which the central atom is involved in sp^3 hybridization is ________. NO_3^-,...
- The Molarity (M) of an aqueous solution containing 5.85 g of NaCl in 500 mL water is: (Given: Molar Mass Na: 23 and Cl: 35.5...
- Identify the correct set of reagents or reaction conditions 'X' and 'Y' in the following set of transformation. CH_3–CH_2–CH_2–Br...
- The correct order of first ionization enthalpy values of the following elements is: (A) O (B) N (C) Be (D) F (E) B Choose the...
- The enthalpy of formation of ethane (C_2H_6) from ethylene by addition of hydrogen where the bond energies of C–H, C–C, C=C, H–H...
- X g of ethylamine is subjected to reaction with NaNO_2/HCl followed by water; evolved dinitrogen gas which occupied 2.24 L volume...
- The de-Broglie's wavelength of an electron in the 4th orbit is _______ πa_0. (a_0 = Bohr's radius)
- Only 2 mL of KMnO_4 solution of unknown molarity is required to reach the end point of a titration of 20 mL of oxalic acid (2 M)...
- Consider the following reaction: MnO_2 + KOH + O_2 → A + H_2O. Product 'A' in neutral or acidic medium disproportionate to give...
- 2.5 g of a non-volatile, non-electrolyte is dissolved in 100 g of water at 25°C. The solution showed a boiling point elevation by...
- The number of different chain isomers for C_7H_ 16 is __________.
- Number of molecules/species from the following having one unpaired electron is ________. O_2, O_2^ -1 , NO, CN^ -1 , O_2^ 2-
- The incorrect postulates of the Dalton's atomic theory are: (A) Atoms of different elements differ in mass. (B) Matter consists...
- The following reaction occurs in the Blast furnance where iron ore is reduced to iron metal: Fe_2O_3(s) + 3CO(g) ⇌ Fe(l) +...
- Given below are two statements: One is labeled as Assertion (A) and the other is labelled as Reason (R) Assertion (A): Enthalpy...
- The statement (s) that are correct about the species O^ 2- , F^-, Na^+ and Mg^ 2+ . (A) All are isoelectronic (B) All have the...
- For the compounds: (A) H_3C–CH_2–O–CH_2–CH_2–CH_3 (B) H_3C–CH_2–CH_2–CH_2–CH_3 (C) CH_3–CH_2–C(=O)–CH_2–CH_3 (D)...
- Given below are two statements: Statement I: In group 13, the stability of +1 oxidation state increases down the group. Statement...
- Number of σ and π bonds present in ethylene molecule is respectively:
- The reaction at cathode in the cells commonly used in clocks involves.