The metal which lies below in the reactivity series CANNOT displace the metal which lies above it. Similarly if the metal lies above in the reactivity series, it CAN displace the metal lying low in the series.

In A part, the reaction follows

$BaCl_2+ Ca\rightarrow CaCl_2+Ba$

Here Ca metal lies low in the series than Ba, therefore it cannot displace Ba metal in the reaction.

In B part ,the reaction follows

$BaCl_2+Sr\rightarrow SrCl_2+Ba$

Here also Sr metal lies low in the series, therefore it cannot displace Ba.

In C part, the reaction follows

$BaCl_2+2Na\rightarrow 2NaCl+Ba$

Here Na metal lies above in the series than Ba, therefore it can easily displace Ba in the reaction and will lead to form NaCl as a product.

In D part, the reaction follows

$BaCl_2+Mg\rightarrow MgCl_2+Ba$

Here Mg lies low in the series, therefore it cannot displace Ba in the reaction.

You can use the image attached.

6 0

4 years ago

Someone help me out with this brain pop ⚠️

erik [133]

The answer is b because if you’re fan is blowing and you spend it the opposite way, the air will be cooler

6 0

3 years ago