Sodium Thiosulphate

Q.

What is milk of lime?

Q.

The reaction of sodium thiosulphate with $I_2$ produces:

1. Sodium sulphite

2. Sodium sulphate

3. Sodium iodide

4. Sodium tetrathionate

Q. Bleaching powder and bleach solution are produced on a large scale and used in several household products. The effectiveness of bleach solution is often measured by iodometry.

25 mL of household bleach solution was mixed with 30 mL of 0.50 M KI and 10 mL of 4N acetic acid. In the titration of the liberated iodine, 48 mL of 0.25 N $N{a}_2{S}_2{O}_3$ was used to reach the end point. The molarity of the household bleach solution is

1. 0.48 M
2. 0.96 M
3. 0.24 M
4. 0.024 M

Q. One litre of 2M acetic acid is mixed with one litre of 3M ethyl alcohol to form ester $C{H}_{3}COOH+C_2{H}_{5}OH\iff C{H}_{3}COO{C}_2{H}_5+H_{2}O$. The decrease in the initial rate if each solution is diluted by an equal volume of water would be

1. 0.5 times
2. 2 times
3. 4 times
4. 0.25 times

Q.

Sodium thiosulphate could be synthesized by

1. boiling aqueous NaOH with Sulphur

2. heating a solution of a Sodium sulphite with finely powdered S in an alkaline medium

3. Spring’s reaction

4. All of the above

Q.

Which of the following statements are correct

I. Both $LiCl$ and $MgC{l}_2$ are soluble in ethanol

II. Both $LiCl$ and $MgC{l}_2$ are deliquescent

III. $LiCl$ and $MgC{l}_2$ form hydrates like $LiCl.8H_{2}O$ and $MgC{l}_2.2H_{2}O$

IV. $NaHC{O}_3$ used as fire extinguisher

1. I, II, IV correct

2. I, II, III correct

3. All are correct

4. Only III correct

Q. Write the following in the form of a word equation:
Sodium hydroxide reacts with calcium bromide to form calcium hydroxide and sodium bromide. In the formula $CaB{r}_2$​ what does Ca stand for and what is its valency?

1. Sodium hydroxide + calcium bromide = Calcium hydroxide + sodium bromide; calcium; 1
2. Sodium hydroxide + calcium bromide $\leftrightarrow$ Calcium hydroxide + sodium bromide; calcium; 2
3. Sodium hydroxide + calcium bromide $\to$ Calcium hydroxide + sodium bromide; calcium; 2
4. Sodium hydroxide + calcium bromide $\to$ Calcium hydroxide + sodium bromide; potassium; 2

Q. The weight of sulphuric acid needed for dissolving $3gm$ magnesium carbonate is:

1. $3.5gm$
2. $1.7gm$
3. $7.0gm$
4. $17.0gm$

Q. In which pair of ions both the species contain S - S bond?

1. $S_4{O}_6^{2-},S_4{O}_3^{2-}$
2. $S_4{O}_6^{2-},S_2{O}_7^{2-}$
3. $S_2{O}_7^{2-},S_2{O}_3^{2-}$
4. $S_2{O}_7^{2-},S_2{O}_8^{2-}$

Q. How will you prepare the following?
Sodium sulphate from sodium chloride