When dilute hydrochloric acid is added to iron filings,

Complete and balance the following reactions:

$\mathrm{Zn} + \mathrm{NaOH} \to \mathrm{\_\_\_\_\_\_\_\_}+\mathrm{\_\_\_\_\_\_\_}$

When hydrogen is passed over a black solid compound ‘$\mathrm{A}$’, the products are a colourless liquid and a reddish brown metal ‘$\mathrm{B}$’ The substance ‘$\mathrm{B}$’ is divided into two parts and each part is placed in separate test tubes. To one part of the substance ‘$\mathrm{B}$’ dil. $\mathrm{HCI}$ is added and to the other part dil. ${\mathrm{HNO}}_3$ is added.

What would you observe when dil. nitric acid reacts with substance ‘$\mathrm{B}$’ ?

Thin strips of three different metals $\mathrm{A},\mathrm{B}$ and $\mathrm{C}$ are known to be magnesium, copper and iron.

Write down that you would observe in case when the metals are treated as follows:

When each metal is treated with dilute hydrochloric acid and warmed, if necessary.

The diagram below is an arrangement of apparatus for preparing and collecting hydrogen.

Name the substance $\mathrm{X}$.

Complete and balance the following reactions:

$\mathrm{Al} + \mathrm{KOH}+{\mathrm{H}}_2\mathrm{O} \to \mathrm{\_\_\_\_\_\_\_\_}+\mathrm{\_\_\_\_\_\_\_}$

Represent the union of two sets by Venn diagram for each of the following.

$X=\{x | x$ is a prime number between $80$ and $100\}$

$Y=\{y | y$ is an odd number between $90$ and $100\}$

Complete the following word equations:

Sodium hydroxide $+$ zinc $\to$ Hydrogen $+$ .........

When hydrogen is passed over a black solid compound ‘$\mathrm{A}$’, the products are a colourless liquid and a reddish brown metal ‘$\mathrm{B}$’ The substance ‘$\mathrm{B}$’ is divided into two parts and each part is placed in separate test tubes. To one part of the substance ‘$\mathrm{B}$’ dil. $\mathrm{HCI}$ is added and to the other part dil. ${\mathrm{HNO}}_3$ is added.

Give two tests for the colourless liquid formed in the experiment.

The diagram below is an arrangement of apparatus for preparing and collecting hydrogen.

Write the equation for the reaction which takes place with steam and $\mathrm{X}$.