D and F Block Elements MCQ Questions & Answers in Inorganic Chemistry | Chemistry

Learn D and F Block Elements MCQ questions & answers in Inorganic Chemistry are available for students perparing for IIT-JEE, NEET, Engineering and Medical Enternace exam.

141. Which one of the following is an ore of silver?

A Argentite
B Stibnite
C Haematite
D Bauxite
Answer :   Argentite

142. Identify the incorrect statement among the following :

A $$4f$$  and $$5f$$  orbitals are equally shielded.
B $$d$$ - Block  elements show irregular and erratic chemical properties among themselves.
C $$La$$  and $$Lu$$  have partially filled $$d$$ - orbitals and no other partially filled orbitals.
D The chemistry of various lanthanoids is very similar.
Answer :   $$4f$$  and $$5f$$  orbitals are equally shielded.

143. Complete the following reactions.
$$\left( {\text{i}} \right)C{r_2}O_7^{2 - } + 3S{O_2} + 2{H^ + } \to $$       $$2C{r^{3 + }} + \_\_\_ + {H_2}O$$
$$\left( {{\text{ii}}} \right)2MnO_4^ - + 5SO_3^{2 - } + 6{H^ + } \to $$       $$2M{n^{2 + }} + \_\_\_ + 3{H_2}O$$
$$\left( {{\text{iii}}} \right)C{r_2}O_7^{2 - } + 6F{e^{2 + }} + 14{H^ + } \to $$       $$2C{r^{3 + }} + \_\_\_ + 7{H_2}O$$

A $$3SO_4^{2 - },SO_2^{2 - },F{e^{3 + }}$$
B $$3SO_4^{2 - },5SO_4^{2 - },6F{e^{3 + }}$$
C $$3SO_4^{2 - },S{O_2},{K^ + }$$
D $$S,S{O_2},F{e^{3 + }}$$
Answer :   $$3SO_4^{2 - },5SO_4^{2 - },6F{e^{3 + }}$$

144. Which of the following lanthanoids is commonly used?

A Lanthanum
B Nobelium
C Thorium
D Cerium
Answer :   Cerium

145. On addition of small amount of $$KMn{O_4}$$  to concentrated $${H_2}S{O_4},$$  a green oily compound is obtained which is highly explosive in nature. Identify the compound from the following.

A $$M{n_2}{O_7}$$
B $$Mn{O_2}$$
C $$MnS{O_4}$$
D $$M{n_2}{O_3}$$
Answer :   $$M{n_2}{O_7}$$

146. Which of the following statements is not correct about magnetic behaviour of substances?

A Diamagnetic substances are repelled by an applied magnetic field.
B Paramagnetic substances are attracted by an applied magnetic field.
C Magnetic moment of $$n$$  unpaired electrons is given by $$\mu = \sqrt {n\left( {n - 2} \right)} \,B.M.$$
D Magnetic moment increases as the number of unpaired electrons increases.
Answer :   Magnetic moment of $$n$$  unpaired electrons is given by $$\mu = \sqrt {n\left( {n - 2} \right)} \,B.M.$$

147. Which of the following elements is responsible for oxidation of water to $${O_2}$$  in biological processes?

A $$Fe$$
B $$Cu$$
C $$Mn$$
D $$Mo$$
Answer :   $$Mn$$

148. The colour of $$KMn{O_4}$$  disappears when oxalic acid is added to its solution in acidic medium. This can be explained as

A the $$pH$$  of the solution changes on adding oxalic acid, hence $$KMn{O_4}$$  is decolourised
B $$KMn{O_4}$$  oxidises oxalic acid to $$C{O_2}$$  and itself changes to $$M{n^{2 + }}$$  ions which are colourless
C $$KMn{O_4}$$  is oxidised to potassium sulphate which is colourless
D on exposure to air the acidic solution of $$KMn{O_4}$$  becomes colourless
Answer :   the $$pH$$  of the solution changes on adding oxalic acid, hence $$KMn{O_4}$$  is decolourised

149. Which of the following statements is not correct?

A Copper liberates hydrogen from acids.
B In higher oxidation states, manganese forms stable compounds with oxygen and fluorine.
C $$M{n^{3 + }}$$ and $$C{o^{3 + }}$$ are oxidising agents in aqueous solution.
D $$T{i^{2 + }}$$ and $$C{r^{2 + }}$$ are reducing agents in aqueous solution.
Answer :   Copper liberates hydrogen from acids.

150. Actinides

A are all synthetic elements
B include element 104
C have any short lived isotopes
D have variable valency
Answer :   have variable valency