Archives

Which of the following statement (s) about the Modern Periodic Table are incorrect (i) The elements in the Modern Periodic Table are arranged based on their decreasing atomic number (ii) The elements in the Modern Periodic Table are arranged based on their increasing atomic masses (iii) Isotopes are placed in adjoining group (s) in the Periodic Table (iv) The elements in the Modern Periodic Table are arranged based on their increasing atomic number (a) (i) only (b) (i), (ii) and (iii) (c) (i), (ii) and (iv) (d) (iv) only

Answer: (b) (i), (ii) and (iii) Elements in the Modern Periodic Table are arranged based on their increasing atomic number hence option (i) is... View Article

Look at Figure and answer the following questions (a) What change would you observe in the calcium hydroxide solution taken in tube B? (b) Write the reaction involved in test tubes A and B respectively. (c) If ethanol is given instead of ethanoic acid, would you expect the same change? (d) How can a solution of lime water be prepared in the laboratory?

Answer: (a) What change would you observe in the calcium hydroxide solution taken in tube B? Calcium Hydroxide solution taken in tube B would... View Article

A compound C (molecular formula, C2H4O2) reacts with Na – metal to form a compound R and evolves a gas which burns with a pop sound. Compound C on treatment with an alcohol A in presence of an acid forms a sweet-smelling compound S (molecular formula, C3H6O2). On addition of NaOH to C, it also gives R and water. S on treatment with NaOH solution gives back R and A. Identify C, R, A, S and write down the reactions involved.

Answer: Compound C is CH3COOH Compound R is CH3COONa Compound A is C2H5OH Compound S is CH3COOC2H5 (1) Compound C is Ethanoic acid (CH3COOH).... View Article