Question

A few solution were tested with different indicators and results were noted down in the given table.
Fill in the blanks by choosing an appropriate option.

Solution(s) ___(i)___ will have no effect on blue litmus paper while solution(s) ___(ii)___ will turn blue litmus red. Phenolphthalein remains colourless in solution(s) ___(iii)___ while it changes to pink colour in solution(s) ___(iv)___.

Answer 1

$\bullet$ Methyl orange turns red in acidic solutions, yellow in basic solutions and remains orange in neutral solutions.
$\bullet$ China rose solution turns dark pink or magenta in acidic solutions and green in basic solutions. It remains light pink in neutral solutions.
$\bullet$ Blue litmus paper turns red in acidic solutions. It remains blue in basic and neutral solutions.
$\bullet$ Phenolphthalein remains colourless in acidic and neutral solutions but turns pink in basic solutions.

Using this, we can find out the nature of the unidentified solutions.

$\bullet$ Solution V gives dark pink colour with china rose indicator and red colour with methyl orange indicator. From this, we can infer that solution V is acidic in nature.
$\bullet$ Similarly, solution W is also acidic in nature.
$\bullet$ Solution X gives light pink colour with china rose indicator and orange colour with methyl orange indicator. This means that solution X does not change the original colours of the china rose and methyl orange indicator. From this, we can infer that solution X is neutral in nature.
$\bullet$ Similarly, solution Z is also neutral in nature.
$\bullet$ Solution Y gives green colour with china rose indicator and yellow colour with methyl orange indicator. From this, we can infer that solution Y is basic in nature.

Based on this table, let’s fill in the blanks.

$\bullet$ Solution (i) has no effect on blue litmus paper. This means that solution (i) is either neutral or basic in nature. From the table, we can conclude that solution (i) can be either solution X, Y or Z.
$\bullet$ Solution (ii) turns blue litmus red. This means that solution (ii) is acidic in nature. From the table, we can conclude that solution (ii) can be either solution V or W.
$\bullet$ Phenophthalein remains colourless in solution (iii). This means that solution (iii) is either neutral or acidic in nature.
$\bullet$ From the table, we can conclude that solution (iii) can be either solution V, W, X or Z.
$\bullet$ Phenolphthalein turns pink in solution (iv). This means that solution (iv) is basic in nature.
$\bullet$ From the table, we can conclude that solution (iv) can be solution Y.

Among the given options, only option B has the correct set of options. Therefore, it is correct.