$Taxa$ differs from $taxon$ due to being

The gas that cannot be collected over water is

Two thermometers $X$ and $Y$ have ice points marked at $15^o$ and $25^o$ and steam points marked as $75^o$ and $125^o$ respectively. When thermometer $X$ measures the temperature of a bath as $60^o$ on it,what would thermometer $Y$ read when it is used to measure the temperature of the same bath?

The process of the isolation of a metal by dissolving the ore in a suitable chemical reagent followed by precipitation of the metal by a more electropositive metal is called:

$A$ simple pendulum is executing simple harmonic motion with a time period $T$. If the length of the pendulum is increased by $21\%$,the percentage increase in the time period of the pendulum of increased length is ..... $\%$

In the following reaction,$X$ and $Y$ are respectively:
$CH_3COOH + NH_3$ $\longrightarrow X \stackrel{\Delta}{}$ ${\longrightarrow} Y + H_2O$