Hey there!:
a) 2 HCl + Ca(OH)₂ = CaCl₂ + 2 H₂O
2 moles of HCl reacts with 1 mole of calcium hydroxide it forms calcium chloride , which is precipitate and forms water
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b) Sr(OH)₂ + 2 HNO₃ = Sr(NO₃)₂ + 2 H₂O
One mole of strontium hydroxide reacts with 2 moles of nitric acid produces strontium nitrate and water as shown above
* Acids are HCl and HNO₃ and bases are Ca(OH)₂ and Sr(OH)₂
I hope this will help !!