December 24, 2012

Inorganic Problem from d-Block elements


Q No. 70.b

1. Chief ore of chromium (A) on roasting with Sodium carbonate gives compound (B) and (C). B on acidification gave compound (D) which on treatment with KCl gave compound (E). Identify the compounds A, B, C, D and E. Explain with proper chemical reactions.
ANSWER
(A)
Chromite ore
(B)
Sodium chromate
(C)
Iron (III) oxide
(D)
Sodium dichromate
(E)
Potassium dichromate

2. The chief ore of chromium A on roasting with molten sodium carbonate gives compound B. Compound B on acidification with conc. H2SO4 gives compound C. Compound C on treatment with KCl gives compound D. Identify A, B, C and D. Explain the reactions.
3. A compound of chromium in which chromium exists in + 6 oxidation state. Its chief ore A on roasting with molten alkali gives compound B. This compound B on acidification gives compound C. Compound C on treatment with KCl gives compound D. Identify compounds A, B, C and D. Explain the proper chemical reactions. M–11  / J–12
ANSWER
(A)
Chromite ore
(B)
Sodium chromate
(C)
Sodium dichromate
(D)
Potassium dichromate
4. An element (A) belonging to group 6 and period 4 is silvery white in colour. Red hot A decomposes steam liberating hydrogen and forming B. A also reacts with conc. Sulphuric acid forming C with evolution of SO2. Identify A, B and C. Explain the two reactions. J–07
ANSWER
(A)
Chromium
(B)
Chromic oxide
(C)
Chromic sulphate
5. An element (A) occupying group number 11 and belonging to the 4th period, is reddish brown in colour. (A) is extracted from its mixed sulphide ore (B). A reacts with dil. H2SO4 in the presence of air to form (C). With water C gives a blue compound D. On treatment with conc. nitric acid (A) gives compound (E). Identify (A), (B), (C), (D) and (E). Give the reactions also. J–10
ANSWER
(A)
Copper
(B)
Copper pyrites
(C)
Copper suphate
(D)
Copper sulphate Pentahydrate
(E)
Cupric nitrate
6. An element A occupies group number 11 and period number 4. This metal is extracted from its mixed sulphide ore B. A reacts with dil. H2SO4 in presence of air and forms C which is colourless. With water C gives a blue compound D. Identify A. B, C and D and explain the reactions. M–07
ANSWER
(A)
Copper
(B)
Copper pyrites
(C)
Copper sulphate
(D)
Copper sulphate Pentahydrate
7. An element (A) belonging to Group No. 11 and Period No. 4 is extracted from the pyrite ore. (A) reacts with oxygen at two different temperatures forming compounds (B) and (C). (A) also reacts with conc. HNO3 to give (D) with the evolution of NO2. Find out (A), (B), (C) and (D). Explain the reactions. O–07 / M–10
8. (A) is a reddish brown metal. It belongs to group 11 and period 4 of the periodic table. When heated below 1370 K, (A) gives a black compound (B). When heated above 1370 K, (A) gives a red compound (C). With concentrated nitric acid, (A) liberates NO2 gas and gives compound (D). Identify (A), (B), (C) and (D). Explain the reactions. M–10 / O–07
ANSWER
(A)
Copper
(B)
Cupric oxide
(C)
Cuprous oxide
(D)
Cupric nitrate
9. An element (A) belongs to group number 11 and period number 4. (A) is a reddish brown metal. (A) reacts with HCl in the presence of air and gives compound (B). (A) also reacts with conc. HNO3 to give compound (C) with the liberation of NO2. Identify (A), (B) and (C). Explain the reactions. M-06 / J–11
ANSWER
(A)
Copper
(B)
Copper chloride
(C)
Copper nitrate
10. Compound A is a sulphate compound of group 11 element. This compound is also called as Blue Vitriol. The compound undergoes decomposition at various temperatures.
     100◦C /    230◦C /      720◦C
A ------→ B ------→ C ------→ D
      373K      503K        993K
  Identify the compounds A, B, C and D and give equations. J–09
ANSWER
(A)
Copper sulphate Pentahydrate
(B)
Copper sulphate Monohydrate
(C)
Copper sulphate
(D)
Cupric oxide + SO3
11. An element belongs to group 12 and period 4 is bluish white in colour. (A) reacts with hot conc. H2SO4 forming (B) with the liberation of SO2. (A) also reacts with dil.HNO3 forming (C) with liberation of N2O. Identify (A), (B) and (C). Explain the reactions. O–08
ANSWER
(A)
Zinc
(B)
Zinc sulphate
(C)
Zinc nitrate
12. An element A present in Period No. 4 and Group No. 12 on treatment with dil. HNO3 forms B with the liberation of N2O. A when heated with air at 773 K gives C which is known as philosopher's wool. Identify A. B and C Explain the reactions involved. O–12
ANSWER
(A)
Zinc
(B)
Zinc nitrate
(C)
Zinc oxide (Philosopher's wool)
13. A bluish white metal when treated with dilute nitric acid gives (A) along with zinc nitrate and water. With very dilute nitric acid it gives (B) along with zinc nitrate and water. The metal when heated with air gives (C). What are (A), (B), (C) and (D)? Explain the reactions. O–09
ANSWER
(A)
Nitrous oxide
(B)
Ammonium nitrate
(C)
Zinc oxide (Philosopher's wool)
14. The sulphide ore of an element of group 12 when roasted gave compound A which on reduction with carbon gave the element B. The carbonate C of this element is used for skin diseases. Identify A, B and C and write the required reaction. O–06
ANSWER
(A)
Zinc oxide (Philosopher's wool)
(B)
Zinc
(C)
Zinc carbonate
15. An element A in group number 12 period number 4 is extracted from its sulphide ore. A reacts with O2 present in the air at 773 K to give compound B which is called Philosopher's wool. A reacts with hot NaOH to give compound C. A also reacts with dilute nitric acid and forms compound D with the liberation of N2O. Find out A. B. C and D. Explain the reactions. O–11
ANSWER
(A)
Zinc
(B)
Zinc oxide (Philosopher's wool)
(C)
Sodium zincate
(D)
Zinc nitrate
16. A bluish white metal A present in 4th period and 12th group on heating in air gives a white cloud B. Metal A on treatment with conc. H2SO4 gives the compound C and SO2 gas. Find A, B and C. Explain the reactions.
ANSWER
(A)
Zinc
(B)
Zinc oxide (Philosopher's wool)
(C)
Zinc sulphate
17. Element A which belongs to group 12 and period 4 is a bluish white metal. A reacts with conc. H2SO4 and gives B with the liberation of SO2. With NaOH A gives compound C. Identify A. B and C. Explain the reactions. M–12
ANSWER
(A)
Zinc
(B)
Zinc sulphate
(C)
Sodium zincate
18. The metal B is extracted from the ore A. On treatment with dil. Nitric acid metal B gives a compound C, which is also known as Lunar Caustics. The compound C on treatment with KI gives a yellow precipitate D. Find A, B, C and D. Explain the reactions of the formation of C and D. M–08
ANSWER
(A)
Silver glance / Argentite
(B)
Silver
(C)
Silver nitrate (Lunar caustic)
(D)
Silver iodide
19. An element (A) belongs to group number 11 and period number 5 and is a lustrous white metal. (A) reacts with dil. HNO3 to give (B). (B) with KI gives (C) which is bright yellow coloured precipitate. Identify (A), (B) and (C). Explain the reactions. O–10
ANSWER
(A)
Silver
(B)
Silver nitrate (Lunar caustic)
(C)
Silver iodide
20. Silver reacts with dil. HNO3 to give compound (A) which on heating at 723 K gives (B). (B) on further heating gives (C). Further compound (A) reacts with KBr and gives (D) which is highly useful in photography. Identify (A), (B), (C) and (D) and write the reactions. J–06 / M–09
ANSWER
(A)
Silver nitrate (Lunar caustic)
(B)
Silver Nitrite
(C)
Silver and NO2
(D)
Silver bromide
21. Silver reacts with dil. HNO3 to give compound (A), which on heating at 723 K gives compound (B). (B) on heating gives compound (C). Compound (A) reacts with KBr and gives (D), which is highly useful in photography. Identify (A), (B), (C) and (D). Explain the reactions. M–09 / J–06
ANSWER
(A)
Silver nitrate (Lunar caustic)
(B)
Silver Nitrite
(C)
Silver and NO2
(D)
Silver bromide

INORGANIC CHEMICAL REACTIONS

2 comments:

  1. Sir, is there an easy way to study these probs?

    ReplyDelete
    Replies
    1. Thank you for visiting this blog.
      Try the following:
      1. Know the position (Period & Group)of the elements in the Periodic table.
      2. Remember the Extraction of Metals & its Chemical properties.
      3. Remember the Preparation & Properties of Metal compounds.
      Also Remember,
      i) Metal + Dil. Acid ---> Hydrogen + Metal salt
      ii) Metal + Conc. Acid ---> Metal salt + Water + Anhydride of acid
      iii) Acid acts as Medium + Oxidising Agent (eg, HNO3)
      Similarly, try to simplify to learn easily.
      Advance best wishes.

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