今年内，吉林德惠宝源丰禽业有限公司发生特大火灾，引发“液氨罐”爆炸，造成多人伤亡。液氨也是氨气加压降温液化而成的，氨气$N{H}_3$通常情况下是一种无色、有刺激性气味的气体，密度比空气小，极易溶于水。实验室常用加热氯化铵和熟石灰两种固体混合物来制取氨气，反应的化学方程式为：2$N{H}_4$Cl + Ca$(OH{)}_2$ ===Ca$C{l}_2$ + 2$N{H}_3$↑+ 2$H_2$O。请根据图回答：

    Most elephants are grey. Only a few are white. It's difficult to see a white elephant. When people find a white elephant, they feel excited.

    Long ago, a white elephant was taken to the king. Only the king could have a white elephant. And the white elephant must be a very good one. People wanted to take a look at the animal. On its way to the king, the white elephant attracted(吸引) many people. They ran into the street and shouted, “A white elephant is coming!”

    All the people liked the cute elephant. Some gave it water to drink. Others sang songs to the elephant. A boy put a red hat on the elephant's head.

    Then the elephant came to the king. At last the king saw the white elephant. The king gave it a name himself. The elephant ate from gold dishes and it began a new life.