The EU is responsible for negotiations not national governments, however there needs to be consensus, strongest have to agree on it. Turkey is not in EU.How is it possible for all EU countries to impose 100% tariff on China altogether. EU has so many countries combined together. Some countries are more friendly and others aren't.
I doubt countries like Germany, Turkey, Portugal will follow.
Trade outside the EU is an exclusive responsibility of the EU, rather than the national governments of member countries. This means the EU institutions make laws on trade matters, and negotiate and conclude international trade agreements.