现有五种溶液，分别含下列离子：①Ag⁺②Mg²⁺③Fe²⁺④Al³⁺⑤Fe³⁺．

（1）写出符合下列条件的离子符号：

滴加氯水有明显现象的离子是____ ，加铁粉后溶液增重的是____ ；

（2）向③的溶液中滴加NaOH溶液，现象是____ ，反应过程中属于氧化还原反应的化学方程式　____ ．

    ［1］China's “four great new inventions” in modern times have made the daily life of the public more and more convenient. They are the high-speed railway(HSR), shopping online, shared bikes and mobile phone payment.

    ［2］Living in Hong Kong, I knew them from the papers, the TV and the Internet. But last month I had the chance to experience all of them.

    ［3］As usual, the golden week stopped the traffic. It was hard to get a railway ticket anywhere in the train stations. But I bought a train ticket to Beijing on the Internet and paid for it through Zhifubao. It was even cheaper than it was bought in the station. Then we got on the high-speed train. I was shocked at its speed and quietness. There was no noise which the train made while running. It was reported that China has the longest high-speed railway in the world, which is regarded as a “name card” for China.

    ［4］China's HSR has also gone abroad. In 2014, China finished building its first foreign high-speed rail in Turkey. In June 2015, China and Russia agreed to build the 770 km of high-speed railway connecting Moscow and Kazan. In October 2015, China helped Indonesia to build a high-speed rail between Jakarta and Bandung.

    ［5］Did I feel bored during the trip on the train? Not at all. I bought many cheap and good things in Taobao and Tmall on the Internet through my mobile phone. It's amazing that there are oceans of products in Taobao and Tmall.        ［6］Soon we arrived in Beijing. We got on a bus near the train station.     getting off the bus, my friend told me that the bus stop is far from his home. I thought we would have to spend much money going to his home on a taxi, but it seemed that he wasn't worried about that. He showed me some bikes on the side of the street. They are called shared bikes. We only need to use our mobile phones to scan(扫描) the QuickResponse code(二维码) on shared bikes, then we could ride the bikes anywhere we wanted to go. It was so cool!

阅读文本选段，完成小题。

    鸿蒙以后多少年，只有善于攀援的金丝猴来游。以后又多少年，才有人来到这里。第一个来者黄帝，一来到，黄山命了名。他和浮丘公、容成子上山采药。传说他在三大主峰之一，海拔1840米的光明顶之旁的炼丹峰上，飞升了。

    又几千年，无人攀登这不可攀登的黄山。直到盛唐开元天宝年间，才有个诗人来到。即使在猿猴愁攀登的地方，这位诗人也不愁。在他足下，险阻山道阻不住他。他是李白。他逸兴横飞，登上了海拔1860米的莲花峰，黄山最高峰的绝顶。有诗为证：“丹崖夹石柱，菡萏金芙蓉，伊昔升绝顶，下窥天目松。”李白在想像中看见，浮丘公引来了王子乔，“吹笙舞松风”。他还想“乘桥蹑彩虹”，又想“遗形入无穷”，可见他游兴之浓。

    又数百年，宋代有一位吴龙翰，“上丹崖万仞之巅，夜宿莲花峰顶。霜月洗空，一碧万里。”看来那时候只能这样，白天登山，当天回不去。得在山顶露宿，也是一种享乐。

    可是这以后，元明清数百年内，极大多数旅行家都没有能登上莲花峰顶。汪瓘以“从者七人，二僧与俱”，组成一支浩浩荡荡的登山队，“一仆前持斧斤，剪伐丛莽，一仆鸣金继之，二三人肩糗执剑戟以随”。他们只到了半山寺，狼狈不堪，临峰翘望，败兴而归。只有少数人到达了光明顶。登莲花峰顶的更少了。而三大主峰之中的天都峰，海拔只有1810米，却最险峻，从来没有人上去过。那时有一批诗人，结盟于天都峰下，称天都社。诗倒是写了不少，可登了上去的，没有一个。

    登天都，有记载的，仅后来的普门法师、云水僧、李匡台、方夜和徐霞客。